56811681 has 6 divisors (see below), whose sum is σ = 82061330. Its totient is φ = 37874448.

The previous prime is 56811659. The next prime is 56811697. The reversal of 56811681 is 18611865.

56811681 is a `hidden beast` number, since 568 + 1 + 16 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 45360225 + 11451456 = 6735^2 + 3384^2 .

It is not a de Polignac number, because 56811681 - 2⁶ = 56811617 is a prime.

It is a super-2 number, since 2×56811681² = 6455134196091522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56811641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3156196 + ... + 3156213.

Almost surely, 2^56811681 is an apocalyptic number.

It is an amenable number.

56811681 is a deficient number, since it is larger than the sum of its proper divisors (25249649).

56811681 is a wasteful number, since it uses less digits than its factorization.

56811681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6312415 (or 6312412 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 56811681 is about 7537.3523866143. The cubic root of 56811681 is about 384.4258175128.

The spelling of 56811681 in words is "fifty-six million, eight hundred eleven thousand, six hundred eighty-one".