664880 has 20 divisors (see below), whose sum is σ = 1546032. Its totient is φ = 265920.

The previous prime is 664879. The next prime is 664891. The reversal of 664880 is 88466.

It is a tau number, because it is divible by the number of its divisors (20).

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, 4076 + ... + 4235.

2⁶⁶⁴⁸⁸⁰ is an apocalyptic number.

It is an amenable number.

664880 is an abundant number, since it is smaller than the sum of its proper divisors (881152).

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

664880 is a wasteful number, since it uses less digits than its factorization.

664880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8324 (or 8318 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 664880 is about 815.4017414747. The cubic root of 664880 is about 87.2799367992.

The spelling of 664880 in words is "six hundred sixty-four thousand, eight hundred eighty".