Number of the day: 7570

Properties of the number 7570:

7570 = 2 × 5 × 757 is a sphenic number and squarefree.
7570 has 3 distinct prime factors, 8 divisors, 13 antidivisors and 3024 totatives.
7570 has a prime digit sum 19 in base 10.
7570 is the difference of 2 positive pentagonal numbers in 2 ways.
7570 = 53² + 69² = 1² + 87² is the sum of 2 positive squares in 2 ways.
7570 = 15² + 28² + 81² is the sum of 3 positive squares.
7570² = 4542² + 6056² = 1952² + 7314² = 174² + 7568² = 4680² + 5950² is the sum of 2 positive squares in 4 ways.
7570² is the sum of 3 positive squares.
7570 is a proper divisor of 1427⁴ - 1.
7570 is palindromic in (at least) the following bases: 3, 27, 39, 47, 87, -28, -86, and -87.
7570 in base 3 = 101101101 and consists of only the digits '0' and '1'.
7570 in base 20 = iia and consists of only the digits 'a' and 'i'.
7570 in base 27 = aaa and consists of only the digit 'a'.
7570 in base 35 = 66a and consists of only the digits '6' and 'a'.
7570 in base 39 = 4c4 and consists of only the digits '4' and 'c'.
7570 in base 43 = 442 and consists of only the digits '2' and '4'.
7570 in base 46 = 3QQ and consists of only the digits '3' and 'Q'.
7570 in base 47 = 3K3 and consists of only the digits '3' and 'K'.
7570 in base 61 = 226 and consists of only the digits '2' and '6'.

The number 7570 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A007107: Number of labeled 2-regular digraphs with n nodes.
A048885: Number of nonisomorphic orthogonal arrays OA(4n,4n-1,2,2).
A060879: Intrinsic 9-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.
A069894: Centered square numbers: a(n) = 4*n^2 + 4*n + 2.
A154360: a(n) = 250*n - 180.
A210766: Number of 8-hoops with n symbols and no a-rooted trees.
A252167: T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 2 3 4 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 2 3 4 6 or 7
A264925: G.f.: 1 / Product_{n>=0} (1 - x^(n+5))^((n+1)*(n+2)*(n+3)*(n+4)/4!).
A284990: Triangle T(n,t) read by rows: the number of n X n {0,1} matrices with trace t where each row sum and each column sum is 3.
A299285: Coordination sequence for "tea" 3D uniform tiling.