56531813 has 4 divisors (see below), whose sum is σ = 60880428. Its totient is φ = 52183200.

The previous prime is 56531807. The next prime is 56531887. The reversal of 56531813 is 31813565.

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 35307364 + 21224449 = 5942^2 + 4607^2 .

It is a cyclic number.

It is not a de Polignac number, because 56531813 - 2⁸ = 56531557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 56531813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56531803) 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, 2174288 + ... + 2174313.

It is an arithmetic number, because the mean of its divisors is an integer number (15220107).

Almost surely, 2^56531813 is an apocalyptic number.

It is an amenable number.

56531813 is a deficient number, since it is larger than the sum of its proper divisors (4348615).

56531813 is a wasteful number, since it uses less digits than its factorization.

56531813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4348614.

The product of its digits is 10800, while the sum is 32.

The square root of 56531813 is about 7518.7640606685. The cubic root of 56531813 is about 383.7935200885.

The spelling of 56531813 in words is "fifty-six million, five hundred thirty-one thousand, eight hundred thirteen".