656640672993 has 12 divisors (see below), whose sum is σ = 961839859968. Its totient is φ = 431594808120.

The previous prime is 656640672979. The next prime is 656640673069. The reversal of 656640672993 is 399276046656.

It is a happy number.

656640672993 is a `hidden beast` number, since 6 + 566 + 4 + 0 + 67 + 2 + 9 + 9 + 3 = 666.

It is not a de Polignac number, because 656640672993 - 2²¹ = 656638575841 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 656640672993.

It is not an unprimeable number, because it can be changed into a prime (656640672973) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 513802705 + ... + 513803982.

It is an arithmetic number, because the mean of its divisors is an integer number (80153321664).

Almost surely, 2^656640672993 is an apocalyptic number.

It is an amenable number.

656640672993 is a deficient number, since it is larger than the sum of its proper divisors (305199186975).

656640672993 is a wasteful number, since it uses less digits than its factorization.

656640672993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1027606764 (or 1027606761 counting only the distinct ones).

The product of its (nonzero) digits is 88179840, while the sum is 63.

The spelling of 656640672993 in words is "six hundred fifty-six billion, six hundred forty million, six hundred seventy-two thousand, nine hundred ninety-three".