681304563656 has 16 divisors (see below), whose sum is σ = 1289165747100. Its totient is φ = 337527031104.

The previous prime is 681304563647. The next prime is 681304563691. The reversal of 681304563656 is 656365403186.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 675568924900 + 5735638756 = 821930^2 + 75734^2 .

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 681304563598 and 681304563607.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 390655415 + ... + 390657158.

Almost surely, 2^681304563656 is an apocalyptic number.

It is an amenable number.

681304563656 is a deficient number, since it is larger than the sum of its proper divisors (607861183444).

681304563656 is a wasteful number, since it uses less digits than its factorization.

681304563656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 781312688 (or 781312684 counting only the distinct ones).

The product of its (nonzero) digits is 9331200, while the sum is 53.

The spelling of 681304563656 in words is "six hundred eighty-one billion, three hundred four million, five hundred sixty-three thousand, six hundred fifty-six".