640390025 has 12 divisors (see below), whose sum is σ = 866273424. Its totient is φ = 465738000.

The previous prime is 640389973. The next prime is 640390039. The reversal of 640390025 is 520093046.

It is not a de Polignac number, because 640390025 - 2²⁶ = 573281161 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640390025.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1164071 + ... + 1164620.

It is an arithmetic number, because the mean of its divisors is an integer number (72189452).

Almost surely, 2^640390025 is an apocalyptic number.

It is an amenable number.

640390025 is a deficient number, since it is larger than the sum of its proper divisors (225883399).

640390025 is a wasteful number, since it uses less digits than its factorization.

640390025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2328712 (or 2328707 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 640390025 is about 25305.9286531832. The cubic root of 640390025 is about 861.9488995032.

The spelling of 640390025 in words is "six hundred forty million, three hundred ninety thousand, twenty-five".