56639966689 has 2 divisors, whose sum is σ = 56639966690. Its totient is φ = 56639966688.

The previous prime is 56639966687. The next prime is 56639966717. The reversal of 56639966689 is 98666993665.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 33455336464 + 23184630225 = 182908^2 + 152265^2 .

It is a cyclic number.

It is not a de Polignac number, because 56639966689 - 2¹ = 56639966687 is a prime.

Together with 56639966687, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (56639966687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28319983344 + 28319983345.

It is an arithmetic number, because the mean of its divisors is an integer number (28319983345).

Almost surely, 2^56639966689 is an apocalyptic number.

It is an amenable number.

56639966689 is a deficient number, since it is larger than the sum of its proper divisors (1).

56639966689 is an equidigital number, since it uses as much as digits as its factorization.

56639966689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 680244480, while the sum is 73.

The spelling of 56639966689 in words is "fifty-six billion, six hundred thirty-nine million, nine hundred sixty-six thousand, six hundred eighty-nine".