666390776832 has 792 divisors, whose sum is σ = 2246554267776. Its totient is φ = 189775872000.

The previous prime is 666390776773. The next prime is 666390776833. The reversal of 666390776832 is 238677093666.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (792).

It is a self number, because there is not a number n which added to its sum of digits gives 666390776832.

It is not an unprimeable number, because it can be changed into a prime (666390776833) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1279060732 + ... + 1279061252.

Almost surely, 2^666390776832 is an apocalyptic number.

666390776832 is a gapful number since it is divisible by the number (62) 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 666390776832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1123277133888).

666390776832 is an abundant number, since it is smaller than the sum of its proper divisors (1580163490944).

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

666390776832 is a wasteful number, since it uses less digits than its factorization.

666390776832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 637 (or 605 counting only the distinct ones).

The product of its (nonzero) digits is 82301184, while the sum is 63.

The spelling of 666390776832 in words is "six hundred sixty-six billion, three hundred ninety million, seven hundred seventy-six thousand, eight hundred thirty-two".