668756979 has 40 divisors (see below), whose sum is σ = 1103078592. Its totient is φ = 400379760.

The previous prime is 668756951. The next prime is 668756983. The reversal of 668756979 is 979657866.

668756979 is a `hidden beast` number, since 6 + 68 + 7 + 569 + 7 + 9 = 666.

It is not a de Polignac number, because 668756979 - 2¹² = 668752883 is a prime.

It is a super-2 number, since 2×668756979² = 894471793922412882, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (668756909) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 69432 + ... + 78474.

Almost surely, 2^668756979 is an apocalyptic number.

668756979 is a deficient number, since it is larger than the sum of its proper divisors (434321613).

668756979 is a wasteful number, since it uses less digits than its factorization.

668756979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9149 (or 9140 counting only the distinct ones).

The product of its digits is 34292160, while the sum is 63.

The square root of 668756979 is about 25860.3360186986. The cubic root of 668756979 is about 874.4925401480.

The spelling of 668756979 in words is "six hundred sixty-eight million, seven hundred fifty-six thousand, nine hundred seventy-nine".