644411320 has 128 divisors (see below), whose sum is σ = 1743638400. Its totient is φ = 209664000.

The previous prime is 644411311. The next prime is 644411323. The reversal of 644411320 is 23114446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644411323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 494670 + ... + 495970.

It is an arithmetic number, because the mean of its divisors is an integer number (13622175).

Almost surely, 2^644411320 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 644411320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (871819200).

644411320 is an abundant number, since it is smaller than the sum of its proper divisors (1099227080).

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

644411320 is a wasteful number, since it uses less digits than its factorization.

644411320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1409 (or 1405 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 644411320 is about 25385.2579265998. The cubic root of 644411320 is about 863.7493235677.

Adding to 644411320 its reverse (23114446), we get a palindrome (667525766).

The spelling of 644411320 in words is "six hundred forty-four million, four hundred eleven thousand, three hundred twenty".