56551561 has 4 divisors (see below), whose sum is σ = 61692624. Its totient is φ = 51410500.

The previous prime is 56551553. The next prime is 56551589. The reversal of 56551561 is 16515565.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 56551561 - 2³ = 56551553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56551511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2570515 + ... + 2570536.

It is an arithmetic number, because the mean of its divisors is an integer number (15423156).

Almost surely, 2^56551561 is an apocalyptic number.

It is an amenable number.

56551561 is a deficient number, since it is larger than the sum of its proper divisors (5141063).

56551561 is a wasteful number, since it uses less digits than its factorization.

56551561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5141062.

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

The square root of 56551561 is about 7520.0771937527. The cubic root of 56551561 is about 383.8382044981.

The spelling of 56551561 in words is "fifty-six million, five hundred fifty-one thousand, five hundred sixty-one".