668820688 has 20 divisors (see below), whose sum is σ = 1296255328. Its totient is φ = 334303200.

The previous prime is 668820679. The next prime is 668820697. The reversal of 668820688 is 886028866.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (668820679) and next prime (668820697).

It is a super-2 number, since 2×668820688² = 894642225393586688, which contains 22 as substring.

It is a congruent number.

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, 74995 + ... + 83437.

Almost surely, 2^668820688 is an apocalyptic number.

It is an amenable number.

668820688 is a deficient number, since it is larger than the sum of its proper divisors (627434640).

668820688 is a wasteful number, since it uses less digits than its factorization.

668820688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13402 (or 13396 counting only the distinct ones).

The product of its (nonzero) digits is 1769472, while the sum is 52.

The square root of 668820688 is about 25861.5677792357. The cubic root of 668820688 is about 874.5203087186.

The spelling of 668820688 in words is "six hundred sixty-eight million, eight hundred twenty thousand, six hundred eighty-eight".