56815531 has 4 divisors (see below), whose sum is σ = 57663592. Its totient is φ = 55967472.

The previous prime is 56815483. The next prime is 56815537. The reversal of 56815531 is 13551865.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13551865 = 5 ⋅2710373.

It is a cyclic number.

It is not a de Polignac number, because 56815531 - 2²³ = 48426923 is a prime.

It is a super-2 number, since 2×56815531² = 6456009125623922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56815537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 423930 + ... + 424063.

It is an arithmetic number, because the mean of its divisors is an integer number (14415898).

Almost surely, 2^56815531 is an apocalyptic number.

56815531 is a deficient number, since it is larger than the sum of its proper divisors (848061).

56815531 is an equidigital number, since it uses as much as digits as its factorization.

56815531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 848060.

The product of its digits is 18000, while the sum is 34.

The square root of 56815531 is about 7537.6077770072. The cubic root of 56815531 is about 384.4345012080.

The spelling of 56815531 in words is "fifty-six million, eight hundred fifteen thousand, five hundred thirty-one".