640571900 has 36 divisors (see below), whose sum is σ = 1471812048. Its totient is φ = 241155840.

The previous prime is 640571891. The next prime is 640571999. The reversal of 640571900 is 9175046.

It is a happy number.

It is a super-2 number, since 2×640571900² = 820664718139220000, which contains 22 as substring.

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 186704 + ... + 190103.

It is an arithmetic number, because the mean of its divisors is an integer number (40883668).

Almost surely, 2^640571900 is an apocalyptic number.

It is an amenable number.

640571900 is an abundant number, since it is smaller than the sum of its proper divisors (831240148).

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

640571900 is a wasteful number, since it uses less digits than its factorization.

640571900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376838 (or 376831 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 640571900 is about 25309.5219235765. The cubic root of 640571900 is about 862.0304915078.

The spelling of 640571900 in words is "six hundred forty million, five hundred seventy-one thousand, nine hundred".