666916864 has 24 divisors (see below), whose sum is σ = 1333512180. Its totient is φ = 333457408.

The previous prime is 666916819. The next prime is 666916867. The reversal of 666916864 is 468619666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666916867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160774 + ... + 164869.

Almost surely, 2^666916864 is an apocalyptic number.

666916864 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

666916864 is a deficient number, since it is larger than the sum of its proper divisors (666595316).

666916864 is an equidigital number, since it uses as much as digits as its factorization.

666916864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325665 (or 325645 counting only the distinct ones).

The product of its digits is 2239488, while the sum is 52.

The square root of 666916864 is about 25824.7335707457. The cubic root of 666916864 is about 873.6897348193.

The spelling of 666916864 in words is "six hundred sixty-six million, nine hundred sixteen thousand, eight hundred sixty-four".