56665581 has 16 divisors (see below), whose sum is σ = 90892800. Its totient is φ = 30675888.

The previous prime is 56665579. The next prime is 56665591. The reversal of 56665581 is 18556665.

It is not a de Polignac number, because 56665581 - 2¹ = 56665579 is a prime.

It is a super-2 number, since 2×56665581² = 6421976140135122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56665501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70611 + ... + 71408.

It is an arithmetic number, because the mean of its divisors is an integer number (5680800).

Almost surely, 2^56665581 is an apocalyptic number.

It is an amenable number.

56665581 is a deficient number, since it is larger than the sum of its proper divisors (34227219).

56665581 is a wasteful number, since it uses less digits than its factorization.

56665581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142048.

The product of its digits is 216000, while the sum is 42.

The square root of 56665581 is about 7527.6544155534. The cubic root of 56665581 is about 384.0959978632.

The spelling of 56665581 in words is "fifty-six million, six hundred sixty-five thousand, five hundred eighty-one".