56510721 has 12 divisors (see below), whose sum is σ = 81699072. Its totient is φ = 37640376.

The previous prime is 56510717. The next prime is 56510743. The reversal of 56510721 is 12701565.

56510721 is a `hidden beast` number, since 5 + 651 + 0 + 7 + 2 + 1 = 666.

It is not a de Polignac number, because 56510721 - 2² = 56510717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (56510761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12100 + ... + 16106.

It is an arithmetic number, because the mean of its divisors is an integer number (6808256).

Almost surely, 2^56510721 is an apocalyptic number.

It is an amenable number.

56510721 is a deficient number, since it is larger than the sum of its proper divisors (25188351).

56510721 is a wasteful number, since it uses less digits than its factorization.

56510721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5580 (or 5577 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 56510721 is about 7517.3613056710. The cubic root of 56510721 is about 383.7457830743.

The spelling of 56510721 in words is "fifty-six million, five hundred ten thousand, seven hundred twenty-one".