Number of the day: 42561

Properties of the number 42561:

42561 = 3² × 4729 is the 38110^th composite number and is not squarefree.
42561 has 2 distinct prime factors, 6 divisors, 7 antidivisors and 28368 totatives.
42561 has an oblong digit product 240 in base 10.
42561 = 17³ + 22³ + 30³ is the sum of 3 positive cubes in 1 way.
42561 = 21281² - 21280² = 7095² - 7092² = 2369² - 2360² is the difference of 2 nonnegative squares in 3 ways.
42561 is the difference of 2 positive pentagonal numbers in 1 way.
42561 = 135² + 156² is the sum of 2 positive squares in 1 way.
42561 = 34² + 91² + 182² is the sum of 3 positive squares.
42561² = 6111² + 42120² is the sum of 2 positive squares in 1 way.
42561² is the sum of 3 positive squares.
42561 is a proper divisor of 1223⁸ - 1.
42561 = '4' + '2561' is the concatenation of 2 semiprime numbers.
42561 = '42' + '561' is the concatenation of 2 sphenic numbers.
42561 is palindromic in (at least) base -72.

The number 42561 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A005225: Number of permutations of length n with equal cycles.
A132960: a(n) = n!*Sum_{d|n} (-1)^(d+1)/(d!*(n/d)^d).
A155627: 6^n-4^n+1.
A218868: Triangular array read by rows: T(n,k) is the number of n-permutations that have exactly k distinct cycle lengths.