640389651264 has 224 divisors, whose sum is σ = 2058702105600. Its totient is φ = 193591918080.

The previous prime is 640389651259. The next prime is 640389651271. The reversal of 640389651264 is 462156983046.

640389651264 is a `hidden beast` number, since 6 + 4 + 0 + 38 + 96 + 512 + 6 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 640389651264.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7924149 + ... + 8004555.

It is an arithmetic number, because the mean of its divisors is an integer number (9190634400).

Almost surely, 2^640389651264 is an apocalyptic number.

640389651264 is a gapful number since it is divisible by the number (64) 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 640389651264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1029351052800).

640389651264 is an abundant number, since it is smaller than the sum of its proper divisors (1418312454336).

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

640389651264 is a wasteful number, since it uses less digits than its factorization.

640389651264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80858 (or 80842 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 54.

The spelling of 640389651264 in words is "six hundred forty billion, three hundred eighty-nine million, six hundred fifty-one thousand, two hundred sixty-four".