668634172640 has 288 divisors, whose sum is σ = 1947380569344. Its totient is φ = 215568138240.

The previous prime is 668634172637. The next prime is 668634172721. The reversal of 668634172640 is 46271436866.

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, 285617870 + ... + 285620210.

It is an arithmetic number, because the mean of its divisors is an integer number (6761738088).

Almost surely, 2^668634172640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668634172640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (973690284672).

668634172640 is an abundant number, since it is smaller than the sum of its proper divisors (1278746396704).

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

668634172640 is a wasteful number, since it uses less digits than its factorization.

668634172640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4530 (or 4515 counting only the distinct ones).

The product of its (nonzero) digits is 6967296, while the sum is 53.

The spelling of 668634172640 in words is "six hundred sixty-eight billion, six hundred thirty-four million, one hundred seventy-two thousand, six hundred forty".