56821931 has 2 divisors, whose sum is σ = 56821932. Its totient is φ = 56821930.

The previous prime is 56821909. The next prime is 56821981. The reversal of 56821931 is 13912865.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56821931 is a prime.

It is a super-3 number, since 3×56821931³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 56821891 and 56821900.

It is not a weakly prime, because it can be changed into another prime (56821981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28410965 + 28410966.

It is an arithmetic number, because the mean of its divisors is an integer number (28410966).

Almost surely, 2^56821931 is an apocalyptic number.

56821931 is a deficient number, since it is larger than the sum of its proper divisors (1).

56821931 is an equidigital number, since it uses as much as digits as its factorization.

56821931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 35.

The square root of 56821931 is about 7538.0323029289. The cubic root of 56821931 is about 384.4489355736.

The spelling of 56821931 in words is "fifty-six million, eight hundred twenty-one thousand, nine hundred thirty-one".