644242252 has 12 divisors (see below), whose sum is σ = 1144251640. Its totient is φ = 317313216.

The previous prime is 644242241. The next prime is 644242271. The reversal of 644242252 is 252242446.

644242252 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1201677 + ... + 1202212.

Almost surely, 2^644242252 is an apocalyptic number.

It is an amenable number.

644242252 is a deficient number, since it is larger than the sum of its proper divisors (500009388).

644242252 is a wasteful number, since it uses less digits than its factorization.

644242252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2403960 (or 2403958 counting only the distinct ones).

The product of its digits is 30720, while the sum is 31.

The square root of 644242252 is about 25381.9276651715. The cubic root of 644242252 is about 863.6737790932.

Adding to 644242252 its reverse (252242446), we get a palindrome (896484698).

The spelling of 644242252 in words is "six hundred forty-four million, two hundred forty-two thousand, two hundred fifty-two".