664808 has 8 divisors (see below), whose sum is σ = 1246530. Its totient is φ = 332400.

The previous prime is 664799. The next prime is 664843. The reversal of 664808 is 808466.

It can be written as a sum of positive squares in only one way, i.e., 550564 + 114244 = 742^2 + 338^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an Ulam number.

It is an unprimeable number.

664808 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41543 + ... + 41558.

2⁶⁶⁴⁸⁰⁸ is an apocalyptic number.

It is an amenable number.

664808 is a deficient number, since it is larger than the sum of its proper divisors (581722).

664808 is a wasteful number, since it uses less digits than its factorization.

664808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83107 (or 83103 counting only the distinct ones).

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

The square root of 664808 is about 815.3575902633. The cubic root of 664808 is about 87.2767861643.

The spelling of 664808 in words is "six hundred sixty-four thousand, eight hundred eight".