644934720 has 112 divisors (see below), whose sum is σ = 2136769920. Its totient is φ = 164499456.

The previous prime is 644934713. The next prime is 644934737. The reversal of 644934720 is 27439446.

It is a super-2 number, since 2×644934720² = 831881586122956800, which contains 22 as substring.

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, 7476 + ... + 36684.

Almost surely, 2^644934720 is an apocalyptic number.

644934720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644934720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1068384960).

644934720 is an abundant number, since it is smaller than the sum of its proper divisors (1491835200).

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

644934720 is a wasteful number, since it uses less digits than its factorization.

644934720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29252 (or 29242 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 39.

The square root of 644934720 is about 25395.5649671355. The cubic root of 644934720 is about 863.9831100951.

The spelling of 644934720 in words is "six hundred forty-four million, nine hundred thirty-four thousand, seven hundred twenty".