666697888 has 24 divisors (see below), whose sum is σ = 1313940852. Its totient is φ = 332998656.

The previous prime is 666697879. The next prime is 666697903. The reversal of 666697888 is 888796666.

It can be written as a sum of positive squares in 2 ways, for example, as 626400784 + 40297104 = 25028^2 + 6348^2 .

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, 21456 + ... + 42352.

Almost surely, 2^666697888 is an apocalyptic number.

It is an amenable number.

666697888 is a deficient number, since it is larger than the sum of its proper divisors (647242964).

666697888 is a wasteful number, since it uses less digits than its factorization.

666697888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21904 (or 21896 counting only the distinct ones).

The product of its digits is 41803776, while the sum is 64.

The square root of 666697888 is about 25820.4935661579. The cubic root of 666697888 is about 873.5941016969.

The spelling of 666697888 in words is "six hundred sixty-six million, six hundred ninety-seven thousand, eight hundred eighty-eight".