640304 has 20 divisors (see below), whose sum is σ = 1418064. Its totient is φ = 274368.

The previous prime is 640303. The next prime is 640307. The reversal of 640304 is 403046.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640304.

It is not an unprimeable number, because it can be changed into a prime (640303) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2747 + ... + 2970.

2⁶⁴⁰³⁰⁴ is an apocalyptic number.

It is an amenable number.

640304 is an abundant number, since it is smaller than the sum of its proper divisors (777760).

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

640304 is a wasteful number, since it uses less digits than its factorization.

640304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5732 (or 5726 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 640304 is about 800.1899774429. The cubic root of 640304 is about 86.1910301945.

The spelling of 640304 in words is "six hundred forty thousand, three hundred four".