688944790656 has 512 divisors, whose sum is σ = 2122739136000. Its totient is φ = 219848048640.

The previous prime is 688944790643. The next prime is 688944790661. The reversal of 688944790656 is 656097449886.

688944790656 is a `hidden beast` number, since 6 + 8 + 8 + 94 + 479 + 0 + 65 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1369671301 + ... + 1369671803.

It is an arithmetic number, because the mean of its divisors is an integer number (4145974875).

Almost surely, 2^688944790656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 688944790656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1061369568000).

688944790656 is an abundant number, since it is smaller than the sum of its proper divisors (1433794345344).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

688944790656 is a wasteful number, since it uses less digits than its factorization.

688944790656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 749 (or 731 counting only the distinct ones).

The product of its (nonzero) digits is 627056640, while the sum is 72.

The spelling of 688944790656 in words is "six hundred eighty-eight billion, nine hundred forty-four million, seven hundred ninety thousand, six hundred fifty-six".