668639387025792 has 1792 divisors, whose sum is σ = 2739638055974400. Its totient is φ = 157235276611584.

The previous prime is 668639387025787. The next prime is 668639387025881. The reversal of 668639387025792 is 297520783936866.

668639387025792 is a `hidden beast` number, since 6 + 6 + 8 + 6 + 3 + 9 + 38 + 7 + 0 + 2 + 579 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 2742597723 + ... + 2742841509.

It is an arithmetic number, because the mean of its divisors is an integer number (1528815879450).

Almost surely, 2^{668639387025792} 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 668639387025792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1369819027987200).

668639387025792 is an abundant number, since it is smaller than the sum of its proper divisors (2070998668948608).

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

668639387025792 is a wasteful number, since it uses less digits than its factorization.

668639387025792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243875 (or 243848 counting only the distinct ones).

The product of its (nonzero) digits is 9876142080, while the sum is 81.

The spelling of 668639387025792 in words is "six hundred sixty-eight trillion, six hundred thirty-nine billion, three hundred eighty-seven million, twenty-five thousand, seven hundred ninety-two".