56515561 has 4 divisors (see below), whose sum is σ = 56531412. Its totient is φ = 56499712.

The previous prime is 56515553. The next prime is 56515579. The reversal of 56515561 is 16551565.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18619225 + 37896336 = 4315^2 + 6156^2 .

It is a cyclic number.

It is not a de Polignac number, because 56515561 - 2³ = 56515553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56515541) 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, 201 + ... + 10633.

It is an arithmetic number, because the mean of its divisors is an integer number (14132853).

Almost surely, 2^56515561 is an apocalyptic number.

It is an amenable number.

56515561 is a deficient number, since it is larger than the sum of its proper divisors (15851).

56515561 is a wasteful number, since it uses less digits than its factorization.

56515561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15850.

The product of its digits is 22500, while the sum is 34.

The square root of 56515561 is about 7517.6832202481. The cubic root of 56515561 is about 383.7567383793.

The spelling of 56515561 in words is "fifty-six million, five hundred fifteen thousand, five hundred sixty-one".