640911326328 has 144 divisors (see below), whose sum is σ = 2148109675920. Its totient is φ = 169031536128.

The previous prime is 640911326299. The next prime is 640911326351. The reversal of 640911326328 is 823623119046.

640911326328 is a `hidden beast` number, since 6 + 4 + 0 + 9 + 1 + 1 + 3 + 2 + 632 + 8 = 666.

640911326328 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×640911326328² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3677101 + ... + 3847452.

It is an arithmetic number, because the mean of its divisors is an integer number (14917428305).

Almost surely, 2^640911326328 is an apocalyptic number.

It is an amenable number.

640911326328 is an abundant number, since it is smaller than the sum of its proper divisors (1507198349592).

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

640911326328 is a wasteful number, since it uses less digits than its factorization.

640911326328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7524598 (or 7524578 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The spelling of 640911326328 in words is "six hundred forty billion, nine hundred eleven million, three hundred twenty-six thousand, three hundred twenty-eight".