645637822368 has 768 divisors, whose sum is σ = 2247965540352. Its totient is φ = 157386240000.

The previous prime is 645637822331. The next prime is 645637822409. The reversal of 645637822368 is 863228736546.

It is a super-2 number, since 2×645637822368² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1626291546 + ... + 1626291942.

It is an arithmetic number, because the mean of its divisors is an integer number (2927038464).

Almost surely, 2^645637822368 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 645637822368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1123982770176).

645637822368 is an abundant number, since it is smaller than the sum of its proper divisors (1602327717984).

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

645637822368 is a wasteful number, since it uses less digits than its factorization.

645637822368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657 (or 649 counting only the distinct ones).

The product of its digits is 69672960, while the sum is 60.

It can be divided in two parts, 6456378 and 22368, that added together give a palindrome (6478746).

The spelling of 645637822368 in words is "six hundred forty-five billion, six hundred thirty-seven million, eight hundred twenty-two thousand, three hundred sixty-eight".