Tuesday, February 7, 2017

Number of the day: 272017

Godfrey Harold Hardy was born on this day 140 years ago.

Happy e-Day!

Properties of the number 272017:

272017 = 17 × 16001 is semiprime and squarefree.
272017 has 2 distinct prime factors, 4 divisors, 11 antidivisors and 256000 totatives.
272017 has a prime digit sum 19 in base 10.
272017 = 1360092 - 1360082 = 80092 - 79922 is the difference of 2 nonnegative squares in 2 ways.
272017 is the difference of 2 positive pentagonal numbers in 2 ways.
272017 = 2242 + 4712 = 242 + 5212 is the sum of 2 positive squares in 2 ways.
272017 = 12 + 2042 + 4802 is the sum of 3 positive squares.
2720172 = 1716652 + 2110082 = 1280082 + 2400152 = 250082 + 2708652 = 1054002 + 2507672 is the sum of 2 positive squares in 4 ways.
2720172 is the sum of 3 positive squares.
272017 is a divisor of 8316 - 1.
272017 is an emirpimes in (at least) the following bases: 2, 6, 7, 9, 11, 12, 13, 15, 17, 19, 20, 22, 25, 26, 29, 31, 33, 35, 37, 39, 41, 43, 47, 48, 49, 51, 53, 55, 56, 59, 60, 62, 70, 71, 73, 74, 76, 78, 79, 81, 85, 87, 89, 91, 95, and 96.
272017 is palindromic in (at least) base -97.

Monday, February 6, 2017

Number of the day: 956

Properties of the number 956:

956 = 22 × 239 is the 793th composite number and is not squarefree.
956 has 2 distinct prime factors, 6 divisors, 11 antidivisors and 476 totatives.
956 has an oblong digit sum 20 in base 10.
Reversing the decimal digits of 956 results in a prime.
956 = 2402 - 2382 is the difference of 2 nonnegative squares in 1 way.
956 is the sum of 2 positive triangular numbers.
956 is the difference of 2 positive pentagonal numbers in 1 way.
956 is not the sum of 3 positive squares.
9562 is the sum of 3 positive squares.
956 is a divisor of 4792 - 1.
956 = '95' + '6' is the concatenation of 2 semiprime numbers.
956 is palindromic in (at least) the following bases: 14, 18, and -17.
956 in base 14 = 4c4 and consists of only the digits '4' and 'c'.
956 in base 18 = 2h2 and consists of only the digits '2' and 'h'.
956 in base 30 = 11q and consists of only the digits '1' and 'q'.

The number 956 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A003480: a(n) = 4a(n-1) - 2a(n-2) (n >= 3).
A006313: Numbers n such that n^16 + 1 is prime.
A006314: Numbers n such that n^8 + 1 is prime.
A023359: Number of compositions (ordered partitions) of n into powers of 2.
A060978: |First digit - second digit + third digit - fourth digit ...| = 10.
A087097: Lunar primes (formerly called dismal primes) (cf. A087062).
A161424: Numbers n such that their largest divisor <= sqrt(n) equals 4.
A231145: Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 5 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=n-n%2, read by rows.
A235229: Numbers whose sum of digits is 20.
A238557: Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 8 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=4*floor(n/2), read by rows.

Sunday, February 5, 2017

Number of the day: 491587949916

Properties of the number 491587949916:

491587949916 = 22 × 34 × 7 × 216749537 is composite and not squarefree.
491587949916 has 4 distinct prime factors, 60 divisors, 25 antidivisors and 140453699328 totatives.
491587949916 has an oblong digit sum 72 in base 10.
491587949916 is the difference of 2 nonnegative squares in 10 ways.
491587949916 is the difference of 2 positive pentagonal numbers in 2 ways.
491587949916 is not the sum of 3 positive squares.
4915879499162 = 1390416111002 + 4715147324162 is the sum of 2 positive squares in 1 way.
4915879499162 is the sum of 3 positive squares.
491587949916 is a divisor of 156740640538 - 1.

Saturday, February 4, 2017

Number of the day: 92645

Properties of the number 92645:

92645 = 5 × 7 × 2647 is a sphenic number and squarefree.
92645 has 3 distinct prime factors, 8 divisors, 13 antidivisors and 63504 totatives.
92645 has an emirpimes digit sum 26 in base 10.
Reversing the decimal digits of 92645 results in a prime.
92645 = (190 × 191)/2 + … + (194 × 195)/2 is the sum of at least 2 consecutive triangular numbers in 1 way.
92645 = 463232 - 463222 = 92672 - 92622 = 66212 - 66142 = 13412 - 13062 is the difference of 2 nonnegative squares in 4 ways.
92645 is the difference of 2 positive pentagonal numbers in 4 ways.
92645 = 22 + 152 + 3042 is the sum of 3 positive squares.
926452 = 555872 + 741162 is the sum of 2 positive squares in 1 way.
926452 is the sum of 3 positive squares.
92645 is a divisor of 24118 - 1.
92645 is palindromic in (at least) base -97.

The number 92645 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A205483: L.g.f.: Sum_{n>=1} x^n/n * Product_{d|n} (1 + d*x^n)^d.
A239429: Numbers n such that n^6+6 and n^6-6 are prime.

Friday, February 3, 2017

Number of the day: 425448

Gaston Julia was born on this day 124 years ago.

Properties of the number 425448:

425448 = 23 × 32 × 19 × 311 is the 389632th composite number and is not squarefree.
425448 has 4 distinct prime factors, 48 divisors, 13 antidivisors and 133920 totatives.
425448 is the difference of 2 nonnegative squares in 12 ways.
425448 is the sum of 2 positive triangular numbers.
425448 is the difference of 2 positive pentagonal numbers in 3 ways.
425448 = 1042 + 1942 + 6142 is the sum of 3 positive squares.
4254482 is the sum of 3 positive squares.
425448 is a divisor of 186718 - 1.
425448 in base 47 = 44S4 and consists of only the digits '4' and 'S'.

Thursday, February 2, 2017

Number of the day: 299096

Bartel Leendert van der Waerden was born on this day 114 years ago.

Properties of the number 299096:

299096 = 23 × 73 × 109 is the 273168th composite number and is not squarefree.
299096 has 3 distinct prime factors, 32 divisors, 13 antidivisors and 127008 totatives.
299096 has a semiprime digit sum 35 in base 10.
299096 = 747752 - 747732 = 373892 - 373852 = 106892 - 106752 = 53552 - 53272 = 15752 - 14772 = 8612 - 6652 = 7952 - 5772 = 5612 - 1252 is the difference of 2 nonnegative squares in 8 ways.
299096 = 362 + 1302 + 5302 is the sum of 3 positive squares.
2990962 = 1646402 + 2497042 is the sum of 2 positive squares in 1 way.
2990962 is the sum of 3 positive squares.
299096 is a divisor of 1936 - 1.
299096 = '29909' + '6' is the concatenation of 2 semiprime numbers.

The number 299096 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequence (among others):

Sequence number and description below are taken from OEIS.
A204088: Row sums of A204087.

Wednesday, February 1, 2017

Number of the day: 50777603889348

John Napier was born on this day 467 years ago.

John Napier was born on this day 467 years ago.

Properties of the number 50777603889348:

50777603889348 = 22 × 3 × 7 × 17 × 79 × 733 × 614063 is composite and not squarefree.
50777603889348 has 7 distinct prime factors, 192 divisors, 107 antidivisors and 13463225837568 totatives.
Reversing the decimal digits of 50777603889348 results in a sphenic number.
50777603889348 is the difference of 2 nonnegative squares in 32 ways.
50777603889348 is the difference of 2 positive pentagonal numbers in 14 ways.
50777603889348 = 36642 + 149262 + 71258242 is the sum of 3 positive squares.
507776038893482 = 302359217445602 + 407940448227482 = 238953430067522 + 448037681376602 = 170331742442402 + 478355101562522 = 74815569168482 + 502234144881002 is the sum of 2 positive squares in 4 ways.
507776038893482 is the sum of 3 positive squares.
50777603889348 is a divisor of 15797368744 - 1.