644165422365 has 32 divisors (see below), whose sum is σ = 1056497613696. Its totient is φ = 334954941440.

The previous prime is 644165422349. The next prime is 644165422387. The reversal of 644165422365 is 563224561446.

644165422365 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644165422365 - 2⁴ = 644165422349 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 592777 + ... + 1280513.

It is an arithmetic number, because the mean of its divisors is an integer number (33015550428).

Almost surely, 2^644165422365 is an apocalyptic number.

It is an amenable number.

644165422365 is a deficient number, since it is larger than the sum of its proper divisors (412332191331).

644165422365 is a wasteful number, since it uses less digits than its factorization.

644165422365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 689309.

The product of its digits is 4147200, while the sum is 48.

It can be divided in two parts, 644165 and 422365, that added together give a triangular number (1066530 = T₁₄₆₀).

The spelling of 644165422365 in words is "six hundred forty-four billion, one hundred sixty-five million, four hundred twenty-two thousand, three hundred sixty-five".