56565721 has 4 divisors (see below), whose sum is σ = 56585344. Its totient is φ = 56546100.

The previous prime is 56565713. The next prime is 56565811. The reversal of 56565721 is 12756565.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12756565 = 5 ⋅2551313.

It is a cyclic number.

It is not a de Polignac number, because 56565721 - 2³ = 56565713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56565121) 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, 4545 + ... + 11566.

It is an arithmetic number, because the mean of its divisors is an integer number (14146336).

Almost surely, 2^56565721 is an apocalyptic number.

It is an amenable number.

56565721 is a deficient number, since it is larger than the sum of its proper divisors (19623).

56565721 is a wasteful number, since it uses less digits than its factorization.

56565721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19622.

The product of its digits is 63000, while the sum is 37.

The square root of 56565721 is about 7521.0186145229. The cubic root of 56565721 is about 383.8702383642.

The spelling of 56565721 in words is "fifty-six million, five hundred sixty-five thousand, seven hundred twenty-one".