644673228 has 48 divisors (see below), whose sum is σ = 1521859584. Its totient is φ = 212388480.

The previous prime is 644673223. The next prime is 644673229. The reversal of 644673228 is 822376446.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 644673228.

It is not an unprimeable number, because it can be changed into a prime (644673221) by changing a digit.

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, 444801 + ... + 446247.

It is an arithmetic number, because the mean of its divisors is an integer number (31705408).

Almost surely, 2^644673228 is an apocalyptic number.

It is an amenable number.

644673228 is an abundant number, since it is smaller than the sum of its proper divisors (877186356).

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

644673228 is a wasteful number, since it uses less digits than its factorization.

644673228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1862 (or 1860 counting only the distinct ones).

The product of its digits is 387072, while the sum is 42.

The square root of 644673228 is about 25390.4160659096. The cubic root of 644673228 is about 863.8663255558.

The spelling of 644673228 in words is "six hundred forty-four million, six hundred seventy-three thousand, two hundred twenty-eight".