645823969992 has 80 divisors (see below), whose sum is σ = 1818899382300. Its totient is φ = 214085255040.

The previous prime is 645823969933. The next prime is 645823970023. The reversal of 645823969992 is 299969328546.

645823969992 is a `hidden beast` number, since 6 + 4 + 582 + 39 + 6 + 9 + 9 + 9 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 633179867076 + 12644102916 = 795726^2 + 112446^2 .

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a self number, because there is not a number n which added to its sum of digits gives 645823969992.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2635867 + ... + 2870442.

Almost surely, 2^645823969992 is an apocalyptic number.

It is an amenable number.

645823969992 is an abundant number, since it is smaller than the sum of its proper divisors (1173075412308).

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

645823969992 is a wasteful number, since it uses less digits than its factorization.

645823969992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5506508 (or 5506495 counting only the distinct ones).

The product of its digits is 453496320, while the sum is 72.

The spelling of 645823969992 in words is "six hundred forty-five billion, eight hundred twenty-three million, nine hundred sixty-nine thousand, nine hundred ninety-two".