644143344 has 80 divisors (see below), whose sum is σ = 1825945632. Its totient is φ = 194448384.

The previous prime is 644143321. The next prime is 644143351. The reversal of 644143344 is 443341446.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23334 + ... + 42810.

Almost surely, 2^644143344 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 644143344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (912972816).

644143344 is an abundant number, since it is smaller than the sum of its proper divisors (1181802288).

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

644143344 is a wasteful number, since it uses less digits than its factorization.

644143344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19554 (or 19548 counting only the distinct ones).

The product of its digits is 55296, while the sum is 33.

The square root of 644143344 is about 25379.9791962090. The cubic root of 644143344 is about 863.6295780090.

The spelling of 644143344 in words is "six hundred forty-four million, one hundred forty-three thousand, three hundred forty-four".