640749772080 has 320 divisors, whose sum is σ = 2410232163840. Its totient is φ = 155167718400.

The previous prime is 640749772063. The next prime is 640749772087. The reversal of 640749772080 is 80277947046.

640749772080 is a `hidden beast` number, since 6 + 4 + 0 + 7 + 497 + 72 + 0 + 80 = 666.

640749772080 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not an unprimeable number, because it can be changed into a prime (640749772087) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 23057074 + ... + 23084846.

It is an arithmetic number, because the mean of its divisors is an integer number (7531975512).

Almost surely, 2^640749772080 is an apocalyptic number.

640749772080 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 640749772080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1205116081920).

640749772080 is an abundant number, since it is smaller than the sum of its proper divisors (1769482391760).

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

640749772080 is a wasteful number, since it uses less digits than its factorization.

640749772080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28777 (or 28765 counting only the distinct ones).

The product of its (nonzero) digits is 4741632, while the sum is 54.

The spelling of 640749772080 in words is "six hundred forty billion, seven hundred forty-nine million, seven hundred seventy-two thousand, eighty".