656640673057 has 4 divisors (see below), whose sum is σ = 657722454016. Its totient is φ = 655558892100.

The previous prime is 656640672979. The next prime is 656640673069. The reversal of 656640673057 is 750376046656.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-656640673057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 656640672989 and 656640673007.

It is not an unprimeable number, because it can be changed into a prime (656640670057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 540889569 + ... + 540890782.

It is an arithmetic number, because the mean of its divisors is an integer number (164430613504).

Almost surely, 2^656640673057 is an apocalyptic number.

It is an amenable number.

656640673057 is a deficient number, since it is larger than the sum of its proper divisors (1081780959).

656640673057 is a wasteful number, since it uses less digits than its factorization.

656640673057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1081780958.

The product of its (nonzero) digits is 19051200, while the sum is 55.

The spelling of 656640673057 in words is "six hundred fifty-six billion, six hundred forty million, six hundred seventy-three thousand, fifty-seven".