665900 has 18 divisors (see below), whose sum is σ = 1445220. Its totient is φ = 266320.

The previous prime is 665897. The next prime is 665921. The reversal of 665900 is 9566.

665900 = 285² + 286² + ... + 292².

It is a self number, because there is not a number n which added to its sum of digits gives 665900.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 665900.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3230 + ... + 3429.

It is an arithmetic number, because the mean of its divisors is an integer number (80290).

2⁶⁶⁵⁹⁰⁰ is an apocalyptic number.

It is an amenable number.

665900 is an abundant number, since it is smaller than the sum of its proper divisors (779320).

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

665900 is a wasteful number, since it uses less digits than its factorization.

665900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6673 (or 6666 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 665900 is about 816.0269603389. The cubic root of 665900 is about 87.3245463775.

The spelling of 665900 in words is "six hundred sixty-five thousand, nine hundred".