644224460 has 96 divisors (see below), whose sum is σ = 1513451520. Its totient is φ = 228384000.

The previous prime is 644224447. The next prime is 644224499. The reversal of 644224460 is 64422446.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1755197 + ... + 1755563.

It is an arithmetic number, because the mean of its divisors is an integer number (15765120).

Almost surely, 2^644224460 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 644224460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (756725760).

644224460 is an abundant number, since it is smaller than the sum of its proper divisors (869227060).

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

644224460 is a wasteful number, since it uses less digits than its factorization.

644224460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567 (or 565 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 32.

The square root of 644224460 is about 25381.5771771575. The cubic root of 644224460 is about 863.6658283442.

The spelling of 644224460 in words is "six hundred forty-four million, two hundred twenty-four thousand, four hundred sixty".