640458992 has 20 divisors (see below), whose sum is σ = 1306199880. Its totient is φ = 303375168.

The previous prime is 640458961. The next prime is 640459007. The reversal of 640458992 is 299854046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1053083 + ... + 1053690.

It is an arithmetic number, because the mean of its divisors is an integer number (65309994).

Almost surely, 2^640458992 is an apocalyptic number.

It is an amenable number.

640458992 is an abundant number, since it is smaller than the sum of its proper divisors (665740888).

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

640458992 is a wasteful number, since it uses less digits than its factorization.

640458992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2106800 (or 2106794 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 47.

The square root of 640458992 is about 25307.2912813679. The cubic root of 640458992 is about 861.9798410095.

It can be divided in two parts, 64045 and 8992, that added together give a palindrome (73037).

The spelling of 640458992 in words is "six hundred forty million, four hundred fifty-eight thousand, nine hundred ninety-two".