640620400 has 60 divisors (see below), whose sum is σ = 1758968272. Its totient is φ = 219640320.

The previous prime is 640620389. The next prime is 640620419. The reversal of 640620400 is 4026046.

640620400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

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, 111597 + ... + 117196.

Almost surely, 2^640620400 is an apocalyptic number.

It is an amenable number.

640620400 is an abundant number, since it is smaller than the sum of its proper divisors (1118347872).

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

640620400 is a wasteful number, since it uses less digits than its factorization.

640620400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228818 (or 228807 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 640620400 is about 25310.4800428597. The cubic root of 640620400 is about 862.0522467673.

Adding to 640620400 its reverse (4026046), we get a palindrome (644646446).

The spelling of 640620400 in words is "six hundred forty million, six hundred twenty thousand, four hundred".