644507704224 has 288 divisors, whose sum is σ = 1947997175040. Its totient is φ = 207308160000.

The previous prime is 644507704021. The next prime is 644507704273. The reversal of 644507704224 is 422407705446.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 644507704224.

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 47 ways as a sum of consecutive naturals, for example, 357860124 + ... + 357861924.

It is an arithmetic number, because the mean of its divisors is an integer number (6763879080).

Almost surely, 2^644507704224 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 644507704224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (973998587520).

644507704224 is an abundant number, since it is smaller than the sum of its proper divisors (1303489470816).

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

644507704224 is a wasteful number, since it uses less digits than its factorization.

644507704224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2313 (or 2268 counting only the distinct ones).

The product of its (nonzero) digits is 1505280, while the sum is 45.

The spelling of 644507704224 in words is "six hundred forty-four billion, five hundred seven million, seven hundred four thousand, two hundred twenty-four".