Number of the day: 4551

Richard Courant was born on this day 131 years ago.

Properties of the number 4551:

4551 = 3 × 37 × 41 is a sphenic number and squarefree.
4551 has 3 distinct prime factors, 8 divisors, 9 antidivisors and 2880 totatives.
4551 has an emirpimes digit sum 15 in base 10.
4551 has a triangular digit sum 15 in base 10.
4551 = 2276² - 2275² = 760² - 757² = 80² - 43² = 76² - 35² is the difference of 2 nonnegative squares in 4 ways.
4551 is the difference of 2 positive pentagonal numbers in 1 way.
4551 is not the sum of 3 positive squares.
4551² = 2385² + 3876² = 999² + 4440² = 495² + 4524² = 1476² + 4305² is the sum of 2 positive squares in 4 ways.
4551² is the sum of 3 positive squares.
4551 is a proper divisor of 739² - 1.
4551 = '4' + '551' is the concatenation of 2 semiprime numbers.
4551 is palindromic in (at least) the following bases: 7, 20, 50, 65, -70, and -91.
4551 in base 7 = 16161 and consists of only the digits '1' and '6'.
4551 in base 17 = fcc and consists of only the digits 'c' and 'f'.
4551 in base 20 = b7b and consists of only the digits '7' and 'b'.
4551 in base 25 = 771 and consists of only the digits '1' and '7'.
4551 in base 27 = 66f and consists of only the digits '6' and 'f'.
4551 in base 47 = 22d and consists of only the digits '2' and 'd'.
4551 in base 49 = 1hh and consists of only the digits '1' and 'h'.
4551 in base 50 = 1f1 and consists of only the digits '1' and 'f'.

The number 4551 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A067707: a(n) = 3*n^2 + 12*n.
A069127: Centered 14-gonal numbers.
A096819: Exponents n such that 2^n-19 is prime.
A111117: Divisors of 10^15 - 1.
A114697: Expansion of (1+x+x^2)/((x-1)*(x+1)*(x^2+2*x-1)); a Pellian-related sequence.
A132310: a(n) = 3^n*Sum_{ k=0..n } binomial(2*k,k)/3^k.
A171271: Numbers n such that phi(n)=2*phi(n-1).
A216840: Smallest palindromic number of 3 digits in two bases differing by n.
A257352: G.f.: (1-2*x+51*x^2)/(1-x)^3.
A278177: T(n,k)=Number of nXk 0..1 arrays with every element both equal and not equal to some elements at offset (-1,0) (-1,1) (0,-1) (0,1) (1,-1) or (1,0), with upper left element zero.