644221932 has 48 divisors (see below), whose sum is σ = 1526568960. Its totient is φ = 211416192.

The previous prime is 644221909. The next prime is 644221969. The reversal of 644221932 is 239122446.

644221932 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 644221893 and 644221902.

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, 432493 + ... + 433979.

It is an arithmetic number, because the mean of its divisors is an integer number (31803520).

Almost surely, 2^644221932 is an apocalyptic number.

It is an amenable number.

644221932 is an abundant number, since it is smaller than the sum of its proper divisors (882347028).

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

644221932 is a wasteful number, since it uses less digits than its factorization.

644221932 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2030 (or 2028 counting only the distinct ones).

The product of its digits is 20736, while the sum is 33.

The square root of 644221932 is about 25381.5273772088. The cubic root of 644221932 is about 863.6646986396.

The spelling of 644221932 in words is "six hundred forty-four million, two hundred twenty-one thousand, nine hundred thirty-two".