644916380 has 12 divisors (see below), whose sum is σ = 1354324440. Its totient is φ = 257966544.

The previous prime is 644916367. The next prime is 644916409. The reversal of 644916380 is 83619446.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

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, 16122890 + ... + 16122929.

It is an arithmetic number, because the mean of its divisors is an integer number (112860370).

Almost surely, 2^644916380 is an apocalyptic number.

It is an amenable number.

644916380 is an abundant number, since it is smaller than the sum of its proper divisors (709408060).

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

644916380 is a wasteful number, since it uses less digits than its factorization.

644916380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32245828 (or 32245826 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 644916380 is about 25395.2038778979. The cubic root of 644916380 is about 863.9749203254.

The spelling of 644916380 in words is "six hundred forty-four million, nine hundred sixteen thousand, three hundred eighty".