56637821 has 2 divisors, whose sum is σ = 56637822. Its totient is φ = 56637820.

The previous prime is 56637811. The next prime is 56637857. The reversal of 56637821 is 12873665.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46308025 + 10329796 = 6805^2 + 3214^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56637821 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56637811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28318910 + 28318911.

It is an arithmetic number, because the mean of its divisors is an integer number (28318911).

Almost surely, 2^56637821 is an apocalyptic number.

It is an amenable number.

56637821 is a deficient number, since it is larger than the sum of its proper divisors (1).

56637821 is an equidigital number, since it uses as much as digits as its factorization.

56637821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60480, while the sum is 38.

The square root of 56637821 is about 7525.8103218192. The cubic root of 56637821 is about 384.0332657994.

The spelling of 56637821 in words is "fifty-six million, six hundred thirty-seven thousand, eight hundred twenty-one".