666879904 has 12 divisors (see below), whose sum is σ = 1312919874. Its totient is φ = 333439936.

The previous prime is 666879901. The next prime is 666879929. The reversal of 666879904 is 409978666.

It can be written as a sum of positive squares in only one way, i.e., 662959504 + 3920400 = 25748^2 + 1980^2 .

It is not an unprimeable number, because it can be changed into a prime (666879901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10419967 + ... + 10420030.

Almost surely, 2^666879904 is an apocalyptic number.

It is an amenable number.

666879904 is a deficient number, since it is larger than the sum of its proper divisors (646039970).

666879904 is a wasteful number, since it uses less digits than its factorization.

666879904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20840007 (or 20839999 counting only the distinct ones).

The product of its (nonzero) digits is 3919104, while the sum is 55.

The square root of 666879904 is about 25824.0179677757. The cubic root of 666879904 is about 873.6735947920.

The spelling of 666879904 in words is "six hundred sixty-six million, eight hundred seventy-nine thousand, nine hundred four".