640658400 has 288 divisors, whose sum is σ = 2199859200. Its totient is φ = 161740800.

The previous prime is 640658393. The next prime is 640658423. The reversal of 640658400 is 4856046.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5877546 + ... + 5877654.

It is an arithmetic number, because the mean of its divisors is an integer number (7638400).

Almost surely, 2^640658400 is an apocalyptic number.

640658400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640658400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1099929600).

640658400 is an abundant number, since it is smaller than the sum of its proper divisors (1559200800).

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

640658400 is a wasteful number, since it uses less digits than its factorization.

640658400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242 (or 229 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 640658400 is about 25311.2307089165. The cubic root of 640658400 is about 862.0692913580.

The spelling of 640658400 in words is "six hundred forty million, six hundred fifty-eight thousand, four hundred".