56687021 has 2 divisors, whose sum is σ = 56687022. Its totient is φ = 56687020.

The previous prime is 56687017. The next prime is 56687047. The reversal of 56687021 is 12078665.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43626025 + 13060996 = 6605^2 + 3614^2 .

It is a cyclic number.

It is not a de Polignac number, because 56687021 - 2² = 56687017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56687321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28343510 + 28343511.

It is an arithmetic number, because the mean of its divisors is an integer number (28343511).

Almost surely, 2^56687021 is an apocalyptic number.

It is an amenable number.

56687021 is a deficient number, since it is larger than the sum of its proper divisors (1).

56687021 is an equidigital number, since it uses as much as digits as its factorization.

56687021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 56687021 is about 7529.0783632527. The cubic root of 56687021 is about 384.1444339666.

The spelling of 56687021 in words is "fifty-six million, six hundred eighty-seven thousand, twenty-one".