644243824 has 40 divisors (see below), whose sum is σ = 1461343968. Its totient is φ = 269368320.

The previous prime is 644243819. The next prime is 644243827. The reversal of 644243824 is 428342446.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644243827) 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 7 ways as a sum of consecutive naturals, for example, 65557 + ... + 74740.

Almost surely, 2^644243824 is an apocalyptic number.

It is an amenable number.

644243824 is an abundant number, since it is smaller than the sum of its proper divisors (817100144).

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

644243824 is a wasteful number, since it uses less digits than its factorization.

644243824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140353 (or 140347 counting only the distinct ones).

The product of its digits is 147456, while the sum is 37.

The square root of 644243824 is about 25381.9586320678. The cubic root of 644243824 is about 863.6744815692.

The spelling of 644243824 in words is "six hundred forty-four million, two hundred forty-three thousand, eight hundred twenty-four".