644252232 has 64 divisors (see below), whose sum is σ = 1763012160. Its totient is φ = 194976000.

The previous prime is 644252201. The next prime is 644252237. The reversal of 644252232 is 232252446.

It is a self number, because there is not a number n which added to its sum of digits gives 644252232.

It is not an unprimeable number, because it can be changed into a prime (644252237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2107 + ... + 35957.

It is an arithmetic number, because the mean of its divisors is an integer number (27547065).

Almost surely, 2^644252232 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 644252232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (881506080).

644252232 is an abundant number, since it is smaller than the sum of its proper divisors (1118759928).

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

644252232 is a wasteful number, since it uses less digits than its factorization.

644252232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33934 (or 33930 counting only the distinct ones).

The product of its digits is 23040, while the sum is 30.

The square root of 644252232 is about 25382.1242609834. The cubic root of 644252232 is about 863.6782388130.

The spelling of 644252232 in words is "six hundred forty-four million, two hundred fifty-two thousand, two hundred thirty-two".