56687681 has 2 divisors, whose sum is σ = 56687682. Its totient is φ = 56687680.

The previous prime is 56687677. The next prime is 56687699. The reversal of 56687681 is 18678665.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56175025 + 512656 = 7495^2 + 716^2 .

It is a cyclic number.

It is not a de Polignac number, because 56687681 - 2² = 56687677 is a prime.

It is a super-2 number, since 2×56687681² = 6426986354315522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (56687611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28343840 + 28343841.

It is an arithmetic number, because the mean of its divisors is an integer number (28343841).

Almost surely, 2^56687681 is an apocalyptic number.

It is an amenable number.

56687681 is a deficient number, since it is larger than the sum of its proper divisors (1).

56687681 is an equidigital number, since it uses as much as digits as its factorization.

56687681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 483840, while the sum is 47.

The square root of 56687681 is about 7529.1221931909. The cubic root of 56687681 is about 384.1459248095.

The spelling of 56687681 in words is "fifty-six million, six hundred eighty-seven thousand, six hundred eighty-one".