644108879232 has 2304 divisors, whose sum is σ = 2666532960000. Its totient is φ = 152750997504.

The previous prime is 644108879159. The next prime is 644108879279. The reversal of 644108879232 is 232978801446.

644108879232 is a `hidden beast` number, since 6 + 441 + 0 + 8 + 87 + 92 + 32 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 10917099619 + ... + 10917099677.

It is an arithmetic number, because the mean of its divisors is an integer number (1157349375).

Almost surely, 2^644108879232 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 644108879232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1333266480000).

644108879232 is an abundant number, since it is smaller than the sum of its proper divisors (2022424080768).

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

644108879232 is a wasteful number, since it uses less digits than its factorization.

644108879232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163 (or 132 counting only the distinct ones).

The product of its (nonzero) digits is 4644864, while the sum is 54.

The spelling of 644108879232 in words is "six hundred forty-four billion, one hundred eight million, eight hundred seventy-nine thousand, two hundred thirty-two".