665904 has 20 divisors (see below), whose sum is σ = 1720376. Its totient is φ = 221952.

The previous prime is 665897. The next prime is 665921. The reversal of 665904 is 409566.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6889 + ... + 6984.

2⁶⁶⁵⁹⁰⁴ is an apocalyptic number.

It is an amenable number.

665904 is an abundant number, since it is smaller than the sum of its proper divisors (1054472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665904 is a wasteful number, since it uses less digits than its factorization.

665904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13884 (or 13878 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 665904 is about 816.0294112347. The cubic root of 665904 is about 87.3247212273.

The spelling of 665904 in words is "six hundred sixty-five thousand, nine hundred four".