644058320 has 20 divisors (see below), whose sum is σ = 1497435780. Its totient is φ = 257623296.

The previous prime is 644058293. The next prime is 644058377. The reversal of 644058320 is 23850446.

It can be written as a sum of positive squares in 2 ways, for example, as 118548544 + 525509776 = 10888^2 + 22924^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×644058320² = 829622239122444800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4025285 + ... + 4025444.

It is an arithmetic number, because the mean of its divisors is an integer number (74871789).

Almost surely, 2^644058320 is an apocalyptic number.

It is an amenable number.

644058320 is an abundant number, since it is smaller than the sum of its proper divisors (853377460).

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

644058320 is a wasteful number, since it uses less digits than its factorization.

644058320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8050742 (or 8050736 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

The square root of 644058320 is about 25378.3041198580. The cubic root of 644058320 is about 863.5915779412.

The spelling of 644058320 in words is "six hundred forty-four million, fifty-eight thousand, three hundred twenty".