664391025 has 48 divisors (see below), whose sum is σ = 1292328000. Its totient is φ = 333492480.

The previous prime is 664391011. The next prime is 664391053. The reversal of 664391025 is 520193466.

It is a happy number.

664391025 is a `hidden beast` number, since 6 + 643 + 9 + 1 + 0 + 2 + 5 = 666.

It is not a de Polignac number, because 664391025 - 2⁴ = 664391009 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 17475 + ... + 40424.

It is an arithmetic number, because the mean of its divisors is an integer number (26923500).

Almost surely, 2^664391025 is an apocalyptic number.

It is an amenable number.

664391025 is a deficient number, since it is larger than the sum of its proper divisors (627936975).

664391025 is a wasteful number, since it uses less digits than its factorization.

664391025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57935 (or 57924 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 664391025 is about 25775.7836932265. The cubic root of 664391025 is about 872.5853535654.

The spelling of 664391025 in words is "six hundred sixty-four million, three hundred ninety-one thousand, twenty-five".