644120354416 has 80 divisors (see below), whose sum is σ = 1609579837440. Its totient is φ = 242302314240.

The previous prime is 644120354389. The next prime is 644120354441. The reversal of 644120354416 is 614453021446.

It is a happy number.

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 15 ways as a sum of consecutive naturals, for example, 8978496 + ... + 9049951.

It is an arithmetic number, because the mean of its divisors is an integer number (20119747968).

Almost surely, 2^644120354416 is an apocalyptic number.

It is an amenable number.

644120354416 is an abundant number, since it is smaller than the sum of its proper divisors (965459483024).

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

644120354416 is a wasteful number, since it uses less digits than its factorization.

644120354416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18028502 (or 18028496 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 40.

The spelling of 644120354416 in words is "six hundred forty-four billion, one hundred twenty million, three hundred fifty-four thousand, four hundred sixteen".