644221416 has 32 divisors (see below), whose sum is σ = 1662508800. Its totient is φ = 207813120.

The previous prime is 644221327. The next prime is 644221439. The reversal of 644221416 is 614122446.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

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, 432201 + ... + 433688.

It is an arithmetic number, because the mean of its divisors is an integer number (51953400).

Almost surely, 2^644221416 is an apocalyptic number.

It is an amenable number.

644221416 is an abundant number, since it is smaller than the sum of its proper divisors (1018287384).

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

644221416 is a wasteful number, since it uses less digits than its factorization.

644221416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 865929 (or 865925 counting only the distinct ones).

The product of its digits is 9216, while the sum is 30.

The square root of 644221416 is about 25381.5172123339. The cubic root of 644221416 is about 863.6644680507.

The spelling of 644221416 in words is "six hundred forty-four million, two hundred twenty-one thousand, four hundred sixteen".