640968400 has 60 divisors (see below), whose sum is σ = 1589632384. Its totient is φ = 248112000.

The previous prime is 640968371. The next prime is 640968443. The reversal of 640968400 is 4869046.

It is a self number, because there is not a number n which added to its sum of digits gives 640968400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13446 + ... + 38245.

Almost surely, 2^640968400 is an apocalyptic number.

It is an amenable number.

640968400 is an abundant number, since it is smaller than the sum of its proper divisors (948663984).

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

640968400 is a wasteful number, since it uses less digits than its factorization.

640968400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51740 (or 51729 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 640968400 is about 25317.3537321735. The cubic root of 640968400 is about 862.2083141653.

The spelling of 640968400 in words is "six hundred forty million, nine hundred sixty-eight thousand, four hundred".