644614944 has 24 divisors (see below), whose sum is σ = 1692114480. Its totient is φ = 214871616.

The previous prime is 644614939. The next prime is 644614981. The reversal of 644614944 is 449416446.

It is a tau number, because it is divible by the number of its divisors (24).

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 644614896 and 644614905.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3357274 + ... + 3357465.

It is an arithmetic number, because the mean of its divisors is an integer number (70504770).

Almost surely, 2^644614944 is an apocalyptic number.

It is an amenable number.

644614944 is an abundant number, since it is smaller than the sum of its proper divisors (1047499536).

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

644614944 is a wasteful number, since it uses less digits than its factorization.

644614944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6714752 (or 6714744 counting only the distinct ones).

The product of its digits is 331776, while the sum is 42.

The square root of 644614944 is about 25389.2682840605. The cubic root of 644614944 is about 863.8402911246.

The spelling of 644614944 in words is "six hundred forty-four million, six hundred fourteen thousand, nine hundred forty-four".