644980908 has 96 divisors (see below), whose sum is σ = 1809384192. Its totient is φ = 176198400.

The previous prime is 644980907. The next prime is 644980933. The reversal of 644980908 is 809089446.

It is not an unprimeable number, because it can be changed into a prime (644980907) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 69418 + ... + 78158.

It is an arithmetic number, because the mean of its divisors is an integer number (18847752).

Almost surely, 2^644980908 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 644980908, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (904692096).

644980908 is an abundant number, since it is smaller than the sum of its proper divisors (1164403284).

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

644980908 is a wasteful number, since it uses less digits than its factorization.

644980908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8815 (or 8813 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 48.

The square root of 644980908 is about 25396.4743222361. The cubic root of 644980908 is about 864.0037347661.

The spelling of 644980908 in words is "six hundred forty-four million, nine hundred eighty thousand, nine hundred eight".