644312732 has 48 divisors (see below), whose sum is σ = 1329011712. Its totient is φ = 267608640.

The previous prime is 644312729. The next prime is 644312761. The reversal of 644312732 is 237213446.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 120557 + ... + 125787.

It is an arithmetic number, because the mean of its divisors is an integer number (27687744).

Almost surely, 2^644312732 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 644312732, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (664505856).

644312732 is an abundant number, since it is smaller than the sum of its proper divisors (684698980).

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

644312732 is a wasteful number, since it uses less digits than its factorization.

644312732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5378 (or 5376 counting only the distinct ones).

The product of its digits is 24192, while the sum is 32.

The square root of 644312732 is about 25383.3160166279. The cubic root of 644312732 is about 863.7052732028.

The spelling of 644312732 in words is "six hundred forty-four million, three hundred twelve thousand, seven hundred thirty-two".