644941069344 has 1440 divisors, whose sum is σ = 2421745869312. Its totient is φ = 165722112000.

The previous prime is 644941069319. The next prime is 644941069363. The reversal of 644941069344 is 443960149446.

644941069344 is a `hidden beast` number, since 6 + 4 + 494 + 106 + 9 + 3 + 44 = 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 239 ways as a sum of consecutive naturals, for example, 15730269964 + ... + 15730270004.

Almost surely, 2^644941069344 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 644941069344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1210872934656).

644941069344 is an abundant number, since it is smaller than the sum of its proper divisors (1776804799968).

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

644941069344 is a wasteful number, since it uses less digits than its factorization.

644941069344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 8957952, while the sum is 54.

The spelling of 644941069344 in words is "six hundred forty-four billion, nine hundred forty-one million, sixty-nine thousand, three hundred forty-four".