644222260 has 24 divisors (see below), whose sum is σ = 1475855136. Its totient is φ = 234262560.

The previous prime is 644222233. The next prime is 644222291. The reversal of 644222260 is 62222446.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1463922 + ... + 1464361.

It is an arithmetic number, because the mean of its divisors is an integer number (61493964).

Almost surely, 2^644222260 is an apocalyptic number.

It is an amenable number.

644222260 is an abundant number, since it is smaller than the sum of its proper divisors (831632876).

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

644222260 is a wasteful number, since it uses less digits than its factorization.

644222260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2928303 (or 2928301 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 28.

The square root of 644222260 is about 25381.5338386001. The cubic root of 644222260 is about 863.6648452153.

The spelling of 644222260 in words is "six hundred forty-four million, two hundred twenty-two thousand, two hundred sixty".