656640670057 has 2 divisors, whose sum is σ = 656640670058. Its totient is φ = 656640670056.

The previous prime is 656640670043. The next prime is 656640670067. The reversal of 656640670057 is 750076046656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 522886625881 + 133754044176 = 723109^2 + 365724^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-656640670057 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 656640669986 and 656640670013.

It is not a weakly prime, because it can be changed into another prime (656640670067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328320335028 + 328320335029.

It is an arithmetic number, because the mean of its divisors is an integer number (328320335029).

Almost surely, 2^656640670057 is an apocalyptic number.

It is an amenable number.

656640670057 is a deficient number, since it is larger than the sum of its proper divisors (1).

656640670057 is an equidigital number, since it uses as much as digits as its factorization.

656640670057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6350400, while the sum is 52.

The spelling of 656640670057 in words is "six hundred fifty-six billion, six hundred forty million, six hundred seventy thousand, fifty-seven".