644377252 has 12 divisors (see below), whose sum is σ = 1134179676. Its totient is φ = 320325920.

The previous prime is 644377247. The next prime is 644377259. The reversal of 644377252 is 252773446.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 404251236 + 240126016 = 20106^2 + 15496^2 .

It is not an unprimeable number, because it can be changed into a prime (644377259) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 464899 + ... + 466282.

It is an arithmetic number, because the mean of its divisors is an integer number (94514973).

Almost surely, 2^644377252 is an apocalyptic number.

It is an amenable number.

644377252 is a deficient number, since it is larger than the sum of its proper divisors (489802424).

644377252 is a wasteful number, since it uses less digits than its factorization.

644377252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 931358 (or 931356 counting only the distinct ones).

The product of its digits is 282240, while the sum is 40.

The square root of 644377252 is about 25384.5868983523. The cubic root of 644377252 is about 863.7341020626.

The spelling of 644377252 in words is "six hundred forty-four million, three hundred seventy-seven thousand, two hundred fifty-two".