664491408 has 80 divisors (see below), whose sum is σ = 2065105920. Its totient is φ = 179860608.

The previous prime is 664491391. The next prime is 664491431. The reversal of 664491408 is 804194466.

664491408 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 664491408.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45660 + ... + 58427.

It is an arithmetic number, because the mean of its divisors is an integer number (25813824).

Almost surely, 2^664491408 is an apocalyptic number.

It is an amenable number.

664491408 is an abundant number, since it is smaller than the sum of its proper divisors (1400614512).

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

664491408 is a wasteful number, since it uses less digits than its factorization.

664491408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104124 (or 104118 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 42.

The square root of 664491408 is about 25777.7308543634. The cubic root of 664491408 is about 872.6292977293.

The spelling of 664491408 in words is "six hundred sixty-four million, four hundred ninety-one thousand, four hundred eight".