665660 has 24 divisors (see below), whose sum is σ = 1418256. Its totient is φ = 262400.

The previous prime is 665659. The next prime is 665677. The reversal of 665660 is 66566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1460 + ... + 1860.

It is an arithmetic number, because the mean of its divisors is an integer number (59094).

2⁶⁶⁵⁶⁶⁰ is an apocalyptic number.

It is an amenable number.

665660 is an abundant number, since it is smaller than the sum of its proper divisors (752596).

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

665660 is a wasteful number, since it uses less digits than its factorization.

665660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493 (or 491 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 665660 is about 815.8798931215. The cubic root of 665660 is about 87.3140541066.

The spelling of 665660 in words is "six hundred sixty-five thousand, six hundred sixty".