56837731021 has 2 divisors, whose sum is σ = 56837731022. Its totient is φ = 56837731020.

The previous prime is 56837731019. The next prime is 56837731079. The reversal of 56837731021 is 12013773865.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56543608521 + 294122500 = 237789^2 + 17150^2 .

It is a cyclic number.

It is not a de Polignac number, because 56837731021 - 2¹ = 56837731019 is a prime.

Together with 56837731019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56837731121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28418865510 + 28418865511.

It is an arithmetic number, because the mean of its divisors is an integer number (28418865511).

Almost surely, 2^56837731021 is an apocalyptic number.

It is an amenable number.

56837731021 is a deficient number, since it is larger than the sum of its proper divisors (1).

56837731021 is an equidigital number, since it uses as much as digits as its factorization.

56837731021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 211680, while the sum is 43.

The spelling of 56837731021 in words is "fifty-six billion, eight hundred thirty-seven million, seven hundred thirty-one thousand, twenty-one".