Friday, July 31, 2020

Number of the day: 22070

Properties of the number 22070:

22070 = 2 × 5 × 2207 is a sphenic number and squarefree.
22070 has 3 distinct prime factors, 8 divisors, 7 antidivisors and 8824 totatives.
22070 has a prime digit sum 11 in base 10.
22070 is the sum of 2 positive triangular numbers.
22070 is the difference of 2 positive pentagonal numbers in 2 ways.
22070 = 102 + 192 + 1472 is the sum of 3 positive squares.
220702 = 132422 + 176562 is the sum of 2 positive squares in 1 way.
220702 is the sum of 3 positive squares.
22070 is a proper divisor of 111103 - 1.
22070 = '2' + '2070' is the concatenation of 2 oblong numbers.
22070 is palindromic in (at least) the following bases: 43, and -32.
22070 in base 31 = mtt and consists of only the digits 'm' and 't'.
22070 in base 43 = BeB and consists of only the digits 'B' and 'e'.
22070 in base 49 = 99K and consists of only the digits '9' and 'K'.
22070 in base 52 = 88M and consists of only the digits '8' and 'M'.

The number 22070 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A004951: Nearest integer to n*phi^16, where phi is the golden ratio, A001622.
A004971: a(n) = ceiling(n*phi^16), where phi is the golden ratio, A001622.
A203552: a(n) = n*(5*n^2 - 3*n + 4) / 6.
A210750: Triangle of coefficients of polynomials v(n,x) jointly generated with A210749; see the Formula section.
A227824: G.f. satisfies: A(x) = Sum_{n>=0} x^n*A(x)^n * Sum_{k=0..n} binomial(n,k)^2 * x^k*(1-x)^(n-k).
A303479: Total volume of the family of rectangular prisms with dimensions p, q, and |q - p| where p divides q, n = p + q and p < q.

Thursday, July 30, 2020

Number of the day: 664269

Properties of the number 664269:

664269 = 3 × 179 × 1237 is a sphenic number and squarefree.
664269 has 3 distinct prime factors, 8 divisors, 17 antidivisors and 440016 totatives.
664269 has a semiprime digit sum 33 in base 10.
664269 = 3321352 - 3321342 = 1107132 - 1107102 = 19452 - 17662 = 8872 - 3502 is the difference of 2 nonnegative squares in 4 ways.
664269 is the sum of 2 positive triangular numbers.
664269 is the difference of 2 positive pentagonal numbers in 2 ways.
664269 = 832 + 882 + 8062 is the sum of 3 positive squares.
6642692 = 3286442 + 5772752 is the sum of 2 positive squares in 1 way.
6642692 is the sum of 3 positive squares.
664269 is a proper divisor of 359206 - 1.

Wednesday, July 29, 2020

Number of the day: 2033

Properties of the number 2033:

2033 is a cyclic number.
2033 = 19 × 107 is semiprime and squarefree.
2033 has 2 distinct prime factors, 4 divisors, 13 antidivisors and 1908 totatives.
2033 has a Fibonacci digit sum 8 in base 10.
Reversing the decimal digits of 2033 results in a sphenic number.
2033 = 10172 - 10162 = 632 - 442 is the difference of 2 nonnegative squares in 2 ways.
2033 is the difference of 2 positive pentagonal numbers in 1 way.
2033 = 42 + 92 + 442 is the sum of 3 positive squares.
20332 is the sum of 3 positive squares.
2033 is a proper divisor of 6439 - 1.
2033 is an emirpimes in (at least) the following bases: 3, 6, 8, 12, 23, 24, 26, 27, 36, 38, 41, 43, 44, 45, 46, 51, 52, 54, 55, 57, 58, 61, 71, 73, 76, 77, 79, 82, 83, 87, 88, 89, 94, and 99.
2033 is palindromic in (at least) the following bases: 5, and -29.
2033 in base 5 = 31113 and consists of only the digits '1' and '3'.
2033 in base 22 = 449 and consists of only the digits '4' and '9'.

The number 2033 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A000107: Number of rooted trees with n nodes and a single labeled node; pointed rooted trees; vertebrates.
A037015: Numbers n with property that, reading binary expansion of n from right to left, run lengths strictly increase.
A037308: Numbers k such that (sum of base-2 digits of k) = (sum of base 10 digits of k).
A046865: Numbers k such that 4*5^k - 1 is prime.
A050969: Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 20.
A055103: Expansion of 4th power of continued fraction 1/ ( 1+q/ ( 1+q^2/ ( 1+q^3/ ( 1+q^4/... )))).
A081464: Fractional part of (3/2)^n decreases monotonically to zero.
A107479: a(n) = a(n-2) + a(n-3) + a(n-4) + a(n-5) + a(n-6) + a(n-7).
A183559: Number of partitions of n containing a clique of size 2.
A198185: T(n,k)=Number of nXk 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 0,2,1,0,0 for x=0,1,2,3,4

Tuesday, July 28, 2020

Number of the day: 4977

Properties of the number 4977:

4977 = 32 × 7 × 79 is the 4310th composite number and is not squarefree.
4977 has 3 distinct prime factors, 12 divisors, 19 antidivisors and 2808 totatives.
4977 = 173 + 43 is the sum of 2 positive cubes in 1 way.
4977 = 253 - 223 is the difference of 2 positive cubes in 1 way.
4977 = 24892 - 24882 = 8312 - 8282 = 3592 - 3522 = 2812 - 2722 = 1292 - 1082 = 712 - 82 is the difference of 2 nonnegative squares in 6 ways.
4977 is the difference of 2 positive pentagonal numbers in 1 way.
4977 = 82 + 172 + 682 is the sum of 3 positive squares.
49772 is the sum of 3 positive squares.
4977 is a proper divisor of 6312 - 1.
4977 = '49' + '77' is the concatenation of 2 semiprime numbers.
4977 is palindromic in (at least) the following bases: 4, 23, 78, and -24.
4977 in base 23 = 999 and consists of only the digit '9'.
4977 in base 31 = 55h and consists of only the digits '5' and 'h'.

The number 4977 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A026906: Number of sums S of distinct positive integers satisfying S <= n.
A055154: Triangle read by rows: T(n,k) = number of k-covers of a labeled n-set, k=1..2^n-1.
A057949: Numbers with more than one factorization into S-primes. See A054520 and A057948 for definition.
A086381: Numbers n such that p=n^2+2 and p+2 are primes.
A122794: Connell (3,2)-sum sequence (partial sums of the (3,2)-Connell sequence).
A193543: E.g.f.: Pi/(sqrt(2)*L) * (1 + 2*Sum_{n>=1} cosh(2*Pi*n*x/L)/cosh(n*Pi)) where L = Lemniscate constant.
A200886: T(n,k)=Number of 0..k arrays x(0..n+1) of n+2 elements without any interior element greater than both neighbors
A203066: T(n,k)=Number of nXk 0..6 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor
A254698: T(n,k)=Number of length n+4 0..k arrays with every five consecutive terms having the maximum of some two terms equal to the minimum of the remaining three terms
A325547: Number of compositions of n with strictly increasing differences.

Monday, July 27, 2020

Number of the day: 4918

Properties of the number 4918:

4918 is the 1241th totient number.
4918 = 2 × 2459 is semiprime and squarefree.
4918 has 2 distinct prime factors, 4 divisors, 11 antidivisors and 2458 totatives.
4918 has a semiprime digit sum 22 in base 10.
Reversing the decimal digits of 4918 results in a sphenic number.
4918 is the difference of 2 positive pentagonal numbers in 2 ways.
4918 = 62 + 112 + 692 is the sum of 3 positive squares.
49182 is the sum of 3 positive squares.
4918 is a proper divisor of 31229 - 1.
4918 is an emirpimes in (at least) the following bases: 2, 3, 4, 5, 8, 11, 14, 15, 16, 19, 21, 23, 26, 29, 30, 33, 35, 37, 40, 45, 50, 51, 52, 54, 56, 60, 65, 70, 71, 73, 74, 79, 80, 87, 89, 97, 98, and 100.
4918 is palindromic in (at least) the following bases: -4, and -39.
4918 in base 6 = 34434 and consists of only the digits '3' and '4'.
4918 in base 9 = 6664 and consists of only the digits '4' and '6'.
4918 in base 26 = 774 and consists of only the digits '4' and '7'.
4918 in base 49 = 22I and consists of only the digits '2' and 'I'.

The number 4918 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A006137: a(n) = 1 + n/2 + 9*n^2/2.
A084381: a(n) = n^3 + 5.
A089395: Prime productive numbers n: Let the digits of n be abcd. Then the numbers bcd*a+1, cd*ab+1, d*abc+1, abcd+1 etc. are all primes. If n is a k-digit number it produces k such primes.
A099411: Numbers n such that 3*R_n + 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A168011: a(n) = Sum of all numbers of divisors of all numbers < (n+1)^2.
A194593: Semiprimes s such that phi(s)/2 is prime.
A204662: Numbers n such that n!8-1 is prime.
A211650: Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^3 < x^3 + y^3.
A215431: Numbers n such that n^128+(n+1)^128 is a prime.
A285799: Number of partitions of n into parts with an odd number of distinct prime divisors.

Sunday, July 26, 2020

Number of the day: 674677

Properties of the number 674677:

674677 is a cyclic number.
674677 is the 54655th prime.
674677 has 33 antidivisors and 674676 totatives.
674677 has an emirp digit sum 37 in base 10.
674677 has sum of divisors equal to 674678 which is semiprime.
674677 = 3373392 - 3373382 is the difference of 2 nonnegative squares in 1 way.
674677 is the sum of 2 positive triangular numbers.
674677 is the difference of 2 positive pentagonal numbers in 1 way.
674677 = 3142 + 7592 is the sum of 2 positive squares in 1 way.
674677 = 302 + 892 + 8162 is the sum of 3 positive squares.
6746772 = 4766522 + 4774852 is the sum of 2 positive squares in 1 way.
6746772 is the sum of 3 positive squares.
674677 is a proper divisor of 4796247 - 1.
674677 = '6' + '74677' is the concatenation of 2 semiprime numbers.
674677 is an emirp in (at least) the following bases: 13, 23, 26, 27, 37, 39, 41, 56, 58, 69, 71, 75, 77, 81, 83, 87, 88, 90, 91, 95, and 100.

Saturday, July 25, 2020

Number of the day: 188521

Properties of the number 188521:

188521 is a cyclic number.
188521 = 53 × 3557 is semiprime and squarefree.
188521 has 2 distinct prime factors, 4 divisors, 15 antidivisors and 184912 totatives.
188521 has a semiprime digit sum 25 in base 10.
188521 = 942612 - 942602 = 18052 - 17522 is the difference of 2 nonnegative squares in 2 ways.
188521 is the difference of 2 positive pentagonal numbers in 2 ways.
188521 = 2752 + 3362 = 1402 + 4112 is the sum of 2 positive squares in 2 ways.
188521 = 1202 + 2112 + 3602 is the sum of 3 positive squares.
1885212 = 995962 + 1600652 = 372712 + 1848002 = 1150802 + 1493212 = 659852 + 1765962 is the sum of 2 positive squares in 4 ways.
1885212 is the sum of 3 positive squares.
188521 is a proper divisor of 193128 - 1.
188521 is an emirpimes in (at least) the following bases: 3, 4, 5, 7, 9, 11, 13, 17, 18, 22, 29, 33, 38, 40, 45, 46, 47, 49, 50, 51, 57, 59, 62, 66, 69, 71, 75, 79, 81, 82, 83, 85, 91, 98, and 99.
188521 is palindromic in (at least) the following bases: 73, -83, and -88.
188521 in base 57 = 111M and consists of only the digits '1' and 'M'.

Friday, July 24, 2020

Number of the day: 367815

Properties of the number 367815:

367815 = 3 × 5 × 7 × 31 × 113 is the 336445th composite number and is squarefree.
367815 has 5 distinct prime factors, 32 divisors, 39 antidivisors and 161280 totatives.
367815 has a sphenic digit sum 30 in base 10.
367815 has an oblong digit sum 30 in base 10.
367815 is the difference of 2 nonnegative squares in 16 ways.
367815 is the difference of 2 positive pentagonal numbers in 5 ways.
367815 is not the sum of 3 positive squares.
3678152 = 2206892 + 2942522 = 1796762 + 3209432 = 2577962 + 2623532 = 488252 + 3645602 is the sum of 2 positive squares in 4 ways.
3678152 is the sum of 3 positive squares.
367815 is a proper divisor of 21112 - 1.
367815 = '36781' + '5' is the concatenation of 2 prime numbers.
367815 is palindromic in (at least) the following bases: 96, and -77.

The number 367815 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequence (among others):

Sequence number and description below are taken from OEIS.
A230498: a(n) is the minimal odd odious k>1, such that k^i, i=2,...,n, all are evil, and a(n)=0, if there is no such k.

Thursday, July 23, 2020

Number of the day: 42049

Properties of the number 42049:

42049 = 7 × 6007 is semiprime and squarefree.
42049 has 2 distinct prime factors, 4 divisors, 15 antidivisors and 36036 totatives.
42049 has a prime digit sum 19 in base 10.
42049 = 13 + 143 + 343 is the sum of 3 positive cubes in 1 way.
42049 = 210252 - 210242 = 30072 - 30002 is the difference of 2 nonnegative squares in 2 ways.
42049 is the sum of 2 positive triangular numbers.
42049 is the difference of 2 positive pentagonal numbers in 2 ways.
42049 = 122 + 172 + 2042 is the sum of 3 positive squares.
420492 is the sum of 3 positive squares.
42049 is a proper divisor of 9722 - 1.
42049 = '4' + '2049' is the concatenation of 2 semiprime numbers.
42049 is an emirpimes in (at least) the following bases: 5, 11, 12, 14, 21, 23, 26, 28, 31, 38, 40, 46, 47, 54, 55, 56, 60, 61, 63, 65, 66, 67, 71, 73, 82, 83, 88, 89, 94, 95, and 99.
42049 is palindromic in (at least) the following bases: 77, -78, and -92.
42049 in base 17 = 8988 and consists of only the digits '8' and '9'.

The number 42049 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A008779: Number of n-dimensional partitions of 5.
A041266: Numerators of continued fraction convergents to sqrt(146).
A042118: Numerators of continued fraction convergents to sqrt(584).
A150579: Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 1), (0, 0, 1), (0, 1, 1), (1, -1, 1), (1, 0, -1)}
A154515: a(n) = 648*n^2 + 72*n + 1.
A157326: a(n) = 10368*n^2 + 288*n + 1.
A157337: a(n) = 128*n^2 + 32*n + 1.
A157433: 128n^2 + 2336n + 10657.
A157919: a(n) = 50*n^2 - 1.
A306973: Numerator of best rational approximation x/y of sqrt(k), y<=k, with k given by A306972. The corresponding denominators are given in A306974.

Wednesday, July 22, 2020

Number of the day: 7222020

Happy Casual π Day!

Properties of the number 7222020:

7222020 = 22 × 3 × 5 × 13 × 47 × 197 is the 6731306th composite number and is not squarefree.
7222020 has 6 distinct prime factors, 96 divisors, 35 antidivisors and 1731072 totatives.
7222020 has an emirpimes digit sum 15 in base 10.
7222020 has a triangular digit sum 15 in base 10.
7222020 is the difference of 2 nonnegative squares in 16 ways.
7222020 is the sum of 2 positive triangular numbers.
7222020 is the difference of 2 positive pentagonal numbers in 7 ways.
7222020 = 2962 + 3502 + 26482 is the sum of 3 positive squares.
72220202 = 51030722 + 51104042 = 43332122 + 57776162 = 34680362 + 63348482 = 27545762 + 66760682 = 17777282 + 69998042 = 7647842 + 71814122 = 45136922 + 56377442 = 36665642 + 62220482 = 27449882 + 66800162 = 36970202 + 62040002 = 27777002 + 66664802 = 18019802 + 69936002 = 10264802 + 71487002 is the sum of 2 positive squares in 13 ways.
72220202 is the sum of 3 positive squares.
7222020 is a proper divisor of 178712 - 1.

Tuesday, July 21, 2020

Number of the day: 56303

Properties of the number 56303:

56303 is a cyclic number.
56303 = 13 × 61 × 71 is a sphenic number and squarefree.
56303 has 3 distinct prime factors, 8 divisors, 19 antidivisors and 50400 totatives.
56303 has an emirp digit sum 17 in base 10.
Reversing the decimal digits of 56303 results in a semiprime.
56303 = 281522 - 281512 = 21722 - 21592 = 4922 - 4312 = 4322 - 3612 is the difference of 2 nonnegative squares in 4 ways.
56303 is the difference of 2 positive pentagonal numbers in 4 ways.
56303 is not the sum of 3 positive squares.
563032 = 216552 + 519722 = 119282 + 550252 = 306722 + 472152 = 101532 + 553802 is the sum of 2 positive squares in 4 ways.
563032 is the sum of 3 positive squares.
56303 is a proper divisor of 8534 - 1.
56303 is palindromic in (at least) the following bases: 65, 81, and -59.

The number 56303 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A077060: Smallest k>A077059(n) such that A077059(n)^2+k^2 is a cube (=A077061(n)^3).
A079403: Let G(t) be the set of numbers between 2^(t-1) and 2^t-1, inclusive. There is a unique number a(t) in G(t) so that the denominator of the a(t)-th partial sum of the double harmonic series is divisible by smaller 2-powers than its neighbors.
A187257: Number of UH^jU's for some j>0, where U=(1,1) and H=(1,1), in all peakless Motzkin paths of length n (can be easily expressed using RNA secondary structure terminology).
A188312: Expansion of (1/(1-x^2))*c(x/((1-x)*(1-x^2))) where c(x) is the g.f. of A000108.
A323266: A323265(n)/2.

Monday, July 20, 2020

Number of the day: 9871

Properties of the number 9871:

9871 is a cyclic number.
9871 is the 1218th prime.
9871 has 5 antidivisors and 9870 totatives.
9871 has a semiprime digit sum 25 in base 10.
Reversing the decimal digits of 9871 results in an emirp.
9871 = 49362 - 49352 is the difference of 2 nonnegative squares in 1 way.
9871 is the sum of 2 positive triangular numbers.
9871 is the difference of 2 positive pentagonal numbers in 1 way.
9871 is not the sum of 3 positive squares.
98712 is the sum of 3 positive squares.
9871 is a proper divisor of 41935 - 1.
9871 = '9' + '871' is the concatenation of 2 semiprime numbers.
9871 = '987' + '1' is the concatenation of 2 Fibonacci numbers.
9871 is an emirp in (at least) the following bases: 5, 10, 11, 17, 18, 20, 35, 41, 42, 43, 44, 45, 52, 53, 55, 56, 59, 61, 65, 69, 74, 76, 77, 87, 88, and 93.
9871 is palindromic in (at least) the following bases: 29, 36, 94, and -71.
9871 in base 3 = 111112121 and consists of only the digits '1' and '2'.
9871 in base 21 = 1181 and consists of only the digits '1' and '8'.
9871 in base 29 = blb and consists of only the digits 'b' and 'l'.
9871 in base 36 = 7m7 and consists of only the digits '7' and 'm'.
9871 in base 37 = 77T and consists of only the digits '7' and 'T'.
9871 in base 40 = 66V and consists of only the digits '6' and 'V'.

The number 9871 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A007810: Largest prime with n distinct decimal digits.
A030540: Largest n-digit norep emirp.
A053072: Primes p such that p-12, p and p+12 are consecutive primes.
A055469: Primes of the form k(k+1)/2+1 (i.e., central polygonal numbers, or one more than triangular numbers).
A071361: Largest n-digit prime with strictly decreasing digits.
A073102: Primes of the form 210n + 1.
A120160: a(n)=ceiling( sum_{i=1..n-1} a(i)/4), a(1)=1.
A188135: a(n) = 8*n^2 + 2*n + 1.
A188382: Primes of the form 8*n^2 + 2*n + 1.
A267503: Primes n such that n-1 is squarefree and all prime divisors of n-1 other than 5 are in the sequence.

Sunday, July 19, 2020

Number of the day: 84889

Properties of the number 84889:

84889 is a cyclic number.
84889 = 7 × 67 × 181 is a sphenic number and squarefree.
84889 has 3 distinct prime factors, 8 divisors, 13 antidivisors and 71280 totatives.
84889 has an emirp digit sum 37 in base 10.
84889 = 73 + 253 + 413 = 283 + 303 + 333 is the sum of 3 positive cubes in 2 ways.
84889 = 424452 - 424442 = 60672 - 60602 = 6672 - 6002 = 3252 - 1442 is the difference of 2 nonnegative squares in 4 ways.
84889 is the sum of 2 positive triangular numbers.
84889 is the difference of 2 positive pentagonal numbers in 4 ways.
84889 = 82 + 932 + 2762 is the sum of 3 positive squares.
848892 = 89112 + 844202 is the sum of 2 positive squares in 1 way.
848892 is the sum of 3 positive squares.
84889 is a proper divisor of 9679 - 1.
84889 in base 45 = ffJ and consists of only the digits 'J' and 'f'.
84889 in base 51 = WWP and consists of only the digits 'P' and 'W'.

The number 84889 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A023596: Convolution of A023532 and Fibonacci numbers.
A135214: a(1)=1, a(n) = a(n-1) + n^5 if n odd, a(n) = a(n-1) + n^4 if n is even.
A232704: Numbers n such that sigma(n)+n divides sigma(n^2).
A331763: Number of vertices formed by drawing the lines connecting any two of the 2*(n+2) perimeter points of a 3 X (n+1) rectangular grid of points (or equally, a 2 X n grid of squares).

Saturday, July 18, 2020

Number of the day: 718570

Properties of the number 718570:

718570 = 2 × 5 × 181 × 397 is the 660641th composite number and is squarefree.
718570 has 4 distinct prime factors, 16 divisors, 19 antidivisors and 285120 totatives.
718570 has a triangular digit sum 28 in base 10.
718570 = (258 × 259)/2 + … + (277 × 278)/2 is the sum of at least 2 consecutive triangular numbers in 1 way.
718570 is the sum of 2 positive triangular numbers.
718570 is the difference of 2 positive pentagonal numbers in 4 ways.
718570 = 5772 + 6212 = 1772 + 8292 = 5572 + 6392 = 892 + 8432 is the sum of 2 positive squares in 4 ways.
718570 = 1352 + 1722 + 8192 is the sum of 3 positive squares.
7185702 = 4311422 + 5748562 = 2229922 + 6830942 = 228062 + 7182082 = 3684162 + 6169382 = 2934662 + 6559122 = 527122 + 7166342 = 4891042 + 5264222 = 1500542 + 7027282 = 980722 + 7118462 = 4721502 + 5416802 = 754302 + 7146002 = 3486502 + 6283202 = 4126802 + 5882502 is the sum of 2 positive squares in 13 ways.
7185702 is the sum of 3 positive squares.
718570 is a proper divisor of 85712 - 1.
718570 = '7185' + '70' is the concatenation of 2 sphenic numbers.

Friday, July 17, 2020

Number of the day: 7172020

Happy Yellow Pig Day!

Properties of the number 7172020:

7172020 = 22 × 5 × 358601 is the 6684448th composite number and is not squarefree.
7172020 has 3 distinct prime factors, 12 divisors, 23 antidivisors and 2868800 totatives.
7172020 has a prime digit sum 19 in base 10.
7172020 = 17930062 - 17930042 = 3586062 - 3585962 is the difference of 2 nonnegative squares in 2 ways.
7172020 is the difference of 2 positive pentagonal numbers in 2 ways.
7172020 = 17562 + 20222 = 5642 + 26182 is the sum of 2 positive squares in 2 ways.
7172020 = 2462 + 2802 + 26522 is the sum of 3 positive squares.
71720202 = 43032122 + 57376162 = 29531042 + 65358282 = 10049482 + 71012642 = 34568002 + 62839802 is the sum of 2 positive squares in 4 ways.
71720202 is the sum of 3 positive squares.
7172020 is a proper divisor of 1031326 - 1.
7172020 in base 3 = 111111101011101 and consists of only the digits '0' and '1'.
7172020 in base 9 = 14441141 and consists of only the digits '1' and '4'.

Thursday, July 16, 2020

Number of the day: 85706

Properties of the number 85706:

85706 = 2 × 42853 is semiprime and squarefree.
85706 has 2 distinct prime factors, 4 divisors, 9 antidivisors and 42852 totatives.
85706 has an emirpimes digit sum 26 in base 10.
Reversing the decimal digits of 85706 results in a sphenic number.
85706 = 2052 + 2092 is the sum of 2 positive squares in 1 way.
85706 = 162 + 652 + 2852 is the sum of 3 positive squares.
857062 = 16562 + 856902 is the sum of 2 positive squares in 1 way.
857062 is the sum of 3 positive squares.
85706 is a proper divisor of 593571 - 1.
85706 = '85' + '706' is the concatenation of 2 semiprime numbers.
85706 is an emirpimes in (at least) the following bases: 3, 5, 9, 15, 34, 35, 36, 39, 40, 44, 46, 50, 51, 52, 53, 54, 55, 58, 59, 61, 67, 82, 89, and 94.
85706 is palindromic in (at least) the following bases: 62, and 87.
85706 in base 62 = MIM and consists of only the digits 'I' and 'M'.

Wednesday, July 15, 2020

Number of the day: 90538

Properties of the number 90538:

90538 = 2 × 7 × 29 × 223 is the 81771th composite number and is squarefree.
90538 has 4 distinct prime factors, 16 divisors, 17 antidivisors and 37296 totatives.
90538 has a semiprime digit sum 25 in base 10.
90538 is the sum of 2 positive triangular numbers.
90538 is the difference of 2 positive pentagonal numbers in 5 ways.
90538 = 92 + 762 + 2912 is the sum of 3 positive squares.
905382 = 624402 + 655622 is the sum of 2 positive squares in 1 way.
905382 is the sum of 3 positive squares.
90538 is a proper divisor of 85312 - 1.
90538 = '905' + '38' is the concatenation of 2 semiprime numbers.
90538 is palindromic in (at least) the following bases: 92, -67, -85, and -96.

The number 90538 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A276901: Number of positive walks with n steps {-3,-2,-1,1,2,3} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.
A278183: Number of n X 2 0..3 arrays with every element plus 1 mod 4 equal to some element at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) or (1,0), with upper left element zero.
A278188: T(n,k)=Number of nXk 0..3 arrays with every element plus 1 mod 4 equal to some element at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) or (1,0), with upper left element zero.

Tuesday, July 14, 2020

Number of the day: 9524

Properties of the number 9524:

9524 = 22 × 2381 is the 8344th composite number and is not squarefree.
9524 has 2 distinct prime factors, 6 divisors, 9 antidivisors and 4760 totatives.
9524 has an oblong digit sum 20 in base 10.
Reversing the decimal digits of 9524 results in a prime.
9524 = (67 × 68)/2 + … + (70 × 71)/2 is the sum of at least 2 consecutive triangular numbers in 1 way.
9524 = 23822 - 23802 is the difference of 2 nonnegative squares in 1 way.
9524 is the difference of 2 positive pentagonal numbers in 1 way.
9524 = 682 + 702 is the sum of 2 positive squares in 1 way.
9524 = 322 + 382 + 842 is the sum of 3 positive squares.
95242 = 2762 + 95202 is the sum of 2 positive squares in 1 way.
95242 is the sum of 3 positive squares.
9524 is a proper divisor of 10217 - 1.
9524 is palindromic in (at least) the following bases: 69, 89, -22, -29, -56, and -69.
9524 in base 13 = 4448 and consists of only the digits '4' and '8'.
9524 in base 28 = c44 and consists of only the digits '4' and 'c'.
9524 in base 32 = 99k and consists of only the digits '9' and 'k'.
9524 in base 34 = 884 and consists of only the digits '4' and '8'.

The number 9524 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A010008: a(0) = 1, a(n) = 18*n^2 + 2 for n>0.
A050256: Diaconis-Mosteller approximation to the Birthday problem function.
A096374: Number of partitions of n such that the least part occurs with even multiplicity.
A108099: a(n) = 8n^2 + 8n + 4.
A117525: Total sum of parts of multiplicity 2 in all partitions of n.
A175287: Partial sums of ceiling(n^2/4).
A188896: Numbers n such that there is no square n-gonal number greater than 1.
A228646: Expansion of g.f. 1/ (1-x^1*(1-x^(m+1))/ (1-x^2*(1-x^(m+2))/ (1- ... ))) for m=6.
A229082: Number of circular permutations i_0, i_1, ..., i_n of 0, 1, ..., n such that all the n+1 numbers i_0^2+i_1, i_1^2+i_2, ..., i_{n-1}^2+i_n, i_n^2+i_0 are of the form (p-1)/2 with p an odd prime.
A273362: Numbers n such that the decimal number concat(7,n) is a square.

Monday, July 13, 2020

Number of the day: 7804

Properties of the number 7804:

7804 = 22 × 1951 is the 6816th composite number and is not squarefree.
7804 has 2 distinct prime factors, 6 divisors, 11 antidivisors and 3900 totatives.
7804 has a prime digit sum 19 in base 10.
Reversing the decimal digits of 7804 results in a semiprime.
7804 = 63 + 93 + 193 is the sum of 3 positive cubes in 1 way.
7804 = 19522 - 19502 is the difference of 2 nonnegative squares in 1 way.
7804 is the difference of 2 positive pentagonal numbers in 1 way.
7804 is not the sum of 3 positive squares.
78042 is the sum of 3 positive squares.
7804 is a proper divisor of 80910 - 1.
7804 is palindromic in (at least) the following bases: 22, 40, -50, and -83.
7804 in base 11 = 5955 and consists of only the digits '5' and '9'.
7804 in base 22 = g2g and consists of only the digits '2' and 'g'.
7804 in base 24 = dd4 and consists of only the digits '4' and 'd'.
7804 in base 25 = cc4 and consists of only the digits '4' and 'c'.
7804 in base 39 = 554 and consists of only the digits '4' and '5'.
7804 in base 40 = 4Z4 and consists of only the digits '4' and 'Z'.

The number 7804 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A014404: Number of ways of getting 5 of a kind, straight flush, 4 of a kind, full house, other flush, other straight, 3 of a kind, 2 pair, a pair or no pair in 5-card poker when joker is wild.
A053080: Number of ways of getting 5 of a kind, royal flush, other straight flush, 4 of a kind, full house, other flush, other straight, 3 of a kind, 2 pair, a pair or no pair in 5-card poker when joker is wild.
A053081: Number of ways of getting no pair, a pair, 2 pair, 3 of a kind, other straight, other flush, full house, 4 of a kind, straight flush or 5 of a kind in 5-card poker when joker is wild.
A078414: a(n) = (a(n-1)+a(n-2))/7^k, where 7^k is the highest power of 7 dividing a(n-1)+a(n-2).
A123284: Number of polyhexes with 24 hexagons, C_(2v) symmetry and containing n carbon atoms.
A153713: Greatest number m such that the fractional part of Pi^A137994(n) <= 1/m.
A153714: Greatest number m such that the fractional part of Pi^A153710(n) <= 1/m.
A256404: Positions of records in A166133.
A283347: T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than two of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly one element.
A292741: Number A(n,k) of partitions of n with k sorts of part 1; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Sunday, July 12, 2020

Number of the day: 7318

Properties of the number 7318:

7318 = 2 × 3659 is semiprime and squarefree.
7318 has 2 distinct prime factors, 4 divisors, 17 antidivisors and 3658 totatives.
7318 has a prime digit sum 19 in base 10.
Reversing the decimal digits of 7318 results in an emirpimes.
7318 is the sum of 2 positive triangular numbers.
7318 is the difference of 2 positive pentagonal numbers in 2 ways.
7318 = 92 + 262 + 812 is the sum of 3 positive squares.
73182 is the sum of 3 positive squares.
7318 is a proper divisor of 55731 - 1.
7318 is an emirpimes in (at least) the following bases: 3, 5, 6, 8, 10, 13, 15, 17, 21, 22, 23, 25, 27, 31, 32, 36, 41, 47, 52, 55, 56, 61, 68, 69, 70, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 84, 88, 94, 95, and 98.
7318 is palindromic in (at least) the following bases: 20, 59, -28, -46, -55, and -62.
7318 in base 3 = 101001001 and consists of only the digits '0' and '1'.
7318 in base 11 = 5553 and consists of only the digits '3' and '5'.
7318 in base 20 = i5i and consists of only the digits '5' and 'i'.
7318 in base 27 = a11 and consists of only the digits '1' and 'a'.
7318 in base 28 = 99a and consists of only the digits '9' and 'a'.
7318 in base 58 = 2AA and consists of only the digits '2' and 'A'.
7318 in base 59 = 262 and consists of only the digits '2' and '6'.

The number 7318 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A001372: Number of mappings (or mapping patterns) from n points to themselves; number of endofunctions.
A042161: Denominators of continued fraction convergents to sqrt(605).
A046746: Sum of smallest parts of all partitions of n.
A141689: Average of Eulerian numbers (A008292) and Pascal's triangle (A007318): t(n,m) = (A008292(n,m) + A007318(n,m))/2.
A212069: Number of (w,x,y,z) with all terms in {1,...,n} and 3*w = x+y+z.
A218563: Numbers n such that n^2 + 1 is divisible by a 4th power.
A218564: Numbers n such that n^2 + 1 is divisible by a 5th power.
A278616: Sum of terms in level n of TRIP -Stern sequence associated with permutation triple (e,13,132).
A323530: Number of square plane partitions of n with strictly decreasing rows and columns.
A325882: Bases b where exactly six primes p with p < b exist such that p is a base-b Wieferich prime.

Saturday, July 11, 2020

Number of the day: 49675

Properties of the number 49675:

49675 = 52 × 1987 is the 44572th composite number and is not squarefree.
49675 has 2 distinct prime factors, 6 divisors, 27 antidivisors and 39720 totatives.
49675 has an emirp digit sum 31 in base 10.
49675 = 248382 - 248372 = 49702 - 49652 = 10062 - 9812 is the difference of 2 nonnegative squares in 3 ways.
49675 is the sum of 2 positive triangular numbers.
49675 is the difference of 2 positive pentagonal numbers in 3 ways.
49675 = 252 + 332 + 2192 is the sum of 3 positive squares.
496752 = 298052 + 397402 = 139092 + 476882 is the sum of 2 positive squares in 2 ways.
496752 is the sum of 3 positive squares.
49675 is a proper divisor of 64760 - 1.
49675 = '4967' + '5' is the concatenation of 2 prime numbers.
49675 is palindromic in (at least) base -62.
49675 in base 47 = MMh and consists of only the digits 'M' and 'h'.
49675 in base 61 = DLL and consists of only the digits 'D' and 'L'.

Friday, July 10, 2020

Number of the day: 9422

Properties of the number 9422:

9422 = 2 × 7 × 673 is a sphenic number and squarefree.
9422 has 3 distinct prime factors, 8 divisors, 11 antidivisors and 4032 totatives.
9422 has an emirp digit sum 17 in base 10.
9422 has a Fibonacci digit product 144 in base 10.
Reversing the decimal digits of 9422 results in a semiprime.
9422 = 22 + 32 + 972 is the sum of 3 positive squares.
94222 = 53902 + 77282 is the sum of 2 positive squares in 1 way.
94222 is the sum of 3 positive squares.
9422 is a proper divisor of 9296 - 1.
9422 = '9' + '422' is the concatenation of 2 semiprime numbers.
9422 is palindromic in (at least) the following bases: 35, 43, and 60.
9422 in base 12 = 5552 and consists of only the digits '2' and '5'.
9422 in base 35 = 7o7 and consists of only the digits '7' and 'o'.
9422 in base 42 = 5EE and consists of only the digits '5' and 'E'.
9422 in base 43 = 545 and consists of only the digits '4' and '5'.
9422 in base 48 = 44E and consists of only the digits '4' and 'E'.
9422 in base 59 = 2ff and consists of only the digits '2' and 'f'.
9422 in base 60 = 2b2 and consists of only the digits '2' and 'b'.

The number 9422 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A091434: Poincar series [or Poincare series] (or Molien series) for a certain four-fold wreath product P_4.
A116271: n times n+9 gives the concatenation of two numbers m and m-3.
A173337: Numbers k>1 such that phi(phi(k))= sigma(sopf(k)).
A196507: a(n) = n*(3*n^2 + 6*n + 1).
A208483: Total sum of the sums of all positive k-th ranks of all partitions of n.
A224197: Least b > p_n^2 such that [p_1^2,p_2^2,...,p_n^2] in base b is prime, where p_j denotes the j-th prime.
A232359: Positions of peak values in A232221.
A248690: Number of words in the n-th book of the King James Version of the Holy Bible.
A272675: Indices where records occur in A265432.
A290574: Self numbers that are the product of two self numbers greater than one.

Thursday, July 9, 2020

Number of the day: 394417

Properties of the number 394417:

394417 is a cyclic number.
394417 = 17 × 23201 is semiprime and squarefree.
394417 has 2 distinct prime factors, 4 divisors, 19 antidivisors and 371200 totatives.
394417 has a triangular digit sum 28 in base 10.
394417 = 1972092 - 1972082 = 116092 - 115922 is the difference of 2 nonnegative squares in 2 ways.
394417 is the sum of 2 positive triangular numbers.
394417 is the difference of 2 positive pentagonal numbers in 2 ways.
394417 = 2312 + 5842 = 712 + 6242 is the sum of 2 positive squares in 2 ways.
394417 = 1432 + 1682 + 5882 is the sum of 3 positive squares.
3944172 = 2698082 + 2876952 = 1856082 + 3480152 = 886082 + 3843352 = 1026802 + 3808172 is the sum of 2 positive squares in 4 ways.
3944172 is the sum of 3 positive squares.
394417 is a proper divisor of 157100 - 1.
394417 = '39' + '4417' is the concatenation of 2 semiprime numbers.
394417 is an emirpimes in (at least) the following bases: 2, 6, 12, 13, 17, 19, 20, 21, 22, 27, 29, 30, 35, 37, 38, 40, 41, 43, 60, 62, 65, 66, 70, 72, 74, 79, 84, 85, 86, 87, 89, 94, 97, 98, 99, and 100.
394417 in base 27 = k111 and consists of only the digits '1' and 'k'.

Wednesday, July 8, 2020

Number of the day: 76700

Henri Cartan was born on this day 116 years ago.

Properties of the number 76700:

76700 = 22 × 52 × 13 × 59 is the 69156th composite number and is not squarefree.
76700 has 4 distinct prime factors, 36 divisors, 15 antidivisors and 27840 totatives.
76700 has an oblong digit sum 20 in base 10.
76700 = 191762 - 191742 = 38402 - 38302 = 14882 - 14622 = 7922 - 7422 = 3842 - 2662 = 3602 - 2302 is the difference of 2 nonnegative squares in 6 ways.
76700 is the difference of 2 positive pentagonal numbers in 6 ways.
76700 is not the sum of 3 positive squares.
767002 = 460202 + 613602 = 188802 + 743402 = 389402 + 660802 = 295002 + 708002 = 214762 + 736322 = 84962 + 762282 = 481442 + 597082 is the sum of 2 positive squares in 7 ways.
767002 is the sum of 3 positive squares.
76700 is a proper divisor of 82720 - 1.
76700 in base 18 = d2d2 and consists of only the digits '2' and 'd'.

Tuesday, July 7, 2020

Number of the day: 471090544

Properties of the number 471090544:

471090544 = 24 × 29443159 is the 446180180th composite number and is not squarefree.
471090544 has 2 distinct prime factors, 10 divisors, 37 antidivisors and 235545264 totatives.
471090544 has a semiprime digit sum 34 in base 10.
471090544 has a Fibonacci digit sum 34 in base 10.
Reversing the decimal digits of 471090544 results in a sphenic number.
471090544 = 1177726372 - 1177726352 = 588863202 - 588863162 = 294431632 - 294431552 is the difference of 2 nonnegative squares in 3 ways.
471090544 is the difference of 2 positive pentagonal numbers in 1 way.
471090544 is not the sum of 3 positive squares.
4710905442 is the sum of 3 positive squares.
471090544 is a proper divisor of 1021220548 - 1.

Monday, July 6, 2020

Number of the day: 3475

Properties of the number 3475:

3475 = 52 × 139 is the 2987th composite number and is not squarefree.
3475 has 2 distinct prime factors, 6 divisors, 11 antidivisors and 2760 totatives.
3475 has a prime digit sum 19 in base 10.
3475 has an oblong digit product 420 in base 10.
Reversing the decimal digits of 3475 results in a prime.
3475 = 17382 - 17372 = 3502 - 3452 = 822 - 572 is the difference of 2 nonnegative squares in 3 ways.
3475 is the sum of 2 positive triangular numbers.
3475 is the difference of 2 positive pentagonal numbers in 3 ways.
3475 = 12 + 152 + 572 is the sum of 3 positive squares.
34752 = 20852 + 27802 = 9732 + 33362 is the sum of 2 positive squares in 2 ways.
34752 is the sum of 3 positive squares.
3475 is a proper divisor of 5574 - 1.
3475 = '347' + '5' is the concatenation of 2 prime numbers.
3475 is palindromic in (at least) base 31.
3475 in base 30 = 3pp and consists of only the digits '3' and 'p'.
3475 in base 31 = 3j3 and consists of only the digits '3' and 'j'.
3475 in base 41 = 22V and consists of only the digits '2' and 'V'.
3475 in base 58 = 11r and consists of only the digits '1' and 'r'.

Sunday, July 5, 2020

Number of the day: 433355

Properties of the number 433355:

433355 is a cyclic number.
433355 = 5 × 13 × 59 × 113 is the 396922th composite number and is squarefree.
433355 has 4 distinct prime factors, 16 divisors, 41 antidivisors and 311808 totatives.
433355 has a prime digit sum 23 in base 10.
433355 = 2166782 - 2166772 = 433382 - 433332 = 166742 - 166612 = 37022 - 36432 = 33662 - 33012 = 19742 - 18612 = 8822 - 5872 = 6662 - 1012 is the difference of 2 nonnegative squares in 8 ways.
433355 is the difference of 2 positive pentagonal numbers in 6 ways.
433355 = 52 + 412 + 6572 is the sum of 3 positive squares.
4333552 = 2600132 + 3466842 = 2116922 + 3781312 = 3037322 + 3091012 = 1066722 + 4200212 = 499732 + 4304642 = 1614832 + 4021442 = 2200112 + 3733522 = 1685042 + 3992532 = 2676242 + 3408432 = 1666752 + 4000202 = 1121002 + 4186052 = 2183002 + 3743552 = 575252 + 4295202 is the sum of 2 positive squares in 13 ways.
4333552 is the sum of 3 positive squares.
433355 is a proper divisor of 10618 - 1.
433355 = '4333' + '55' is the concatenation of 2 semiprime numbers.

Saturday, July 4, 2020

Number of the day: 485480

Properties of the number 485480:

485480 = 23 × 5 × 53 × 229 is the 445065th composite number and is not squarefree.
485480 has 4 distinct prime factors, 32 divisors, 13 antidivisors and 189696 totatives.
485480 has a prime digit sum 29 in base 10.
485480 = 1213712 - 1213692 = 606872 - 606832 = 242792 - 242692 = 121472 - 121272 = 23432 - 22372 = 12512 - 10392 = 7592 - 3012 = 7232 - 1932 is the difference of 2 nonnegative squares in 8 ways.
485480 is the difference of 2 positive pentagonal numbers in 3 ways.
485480 = 4662 + 5182 = 3142 + 6222 = 1222 + 6862 = 622 + 6942 is the sum of 2 positive squares in 4 ways.
485480 = 142 + 1602 + 6782 is the sum of 3 positive squares.
4854802 = 2984962 + 3828722 = 2912882 + 3883842 = 1793522 + 4511362 = 2882882 + 3906162 = 1758722 + 4525042 = 511682 + 4827762 = 1673842 + 4557122 = 421362 + 4836482 = 860562 + 4777922 = 3306002 + 3555202 = 2564802 + 4122002 = 1395202 + 4650002 = 1272002 + 4685202 is the sum of 2 positive squares in 13 ways.
4854802 is the sum of 3 positive squares.
485480 is a proper divisor of 1074 - 1.
485480 is palindromic in (at least) the following bases: 39, and -16.
485480 in base 39 = 8778 and consists of only the digits '7' and '8'.