644283744 has 48 divisors (see below), whose sum is σ = 1821344112. Its totient is φ = 198240768.

The previous prime is 644283733. The next prime is 644283779. The reversal of 644283744 is 447382446.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (48).

It is a junction number, because it is equal to n+sod(n) for n = 644283696 and 644283705.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 256879 + ... + 259374.

It is an arithmetic number, because the mean of its divisors is an integer number (37944669).

Almost surely, 2^644283744 is an apocalyptic number.

It is an amenable number.

644283744 is an abundant number, since it is smaller than the sum of its proper divisors (1177060368).

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

644283744 is a wasteful number, since it uses less digits than its factorization.

644283744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516279 (or 516271 counting only the distinct ones).

The product of its digits is 516096, while the sum is 42.

The square root of 644283744 is about 25382.7450052196. The cubic root of 644283744 is about 863.6923201431.

The spelling of 644283744 in words is "six hundred forty-four million, two hundred eighty-three thousand, seven hundred forty-four".