640684800 has 486 divisors, whose sum is σ = 2676305268. Its totient is φ = 145797120.

The previous prime is 640684799. The next prime is 640684813. The reversal of 640684800 is 8486046.

640684800 is a `hidden beast` number, since 640 + 6 + 8 + 4 + 8 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 2822287 + ... + 2822513.

Almost surely, 2^640684800 is an apocalyptic number.

640684800 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 640684800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1338152634).

640684800 is an abundant number, since it is smaller than the sum of its proper divisors (2035620468).

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

640684800 is a wasteful number, since it uses less digits than its factorization.

640684800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273 (or 244 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 640684800 is about 25311.7522111765. The cubic root of 640684800 is about 862.0811324664.

The spelling of 640684800 in words is "six hundred forty million, six hundred eighty-four thousand, eight hundred".