644253363 has 12 divisors (see below), whose sum is σ = 1002172080. Its totient is φ = 396463536.

The previous prime is 644253359. The next prime is 644253371. The reversal of 644253363 is 363352446.

644253363 is a `hidden beast` number, since 6 + 44 + 253 + 363 = 666.

644253363 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644253363 - 2² = 644253359 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644253373) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2753103 + ... + 2753336.

It is an arithmetic number, because the mean of its divisors is an integer number (83514340).

Almost surely, 2^644253363 is an apocalyptic number.

644253363 is a deficient number, since it is larger than the sum of its proper divisors (357918717).

644253363 is a wasteful number, since it uses less digits than its factorization.

644253363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5506458 (or 5506455 counting only the distinct ones).

The product of its digits is 155520, while the sum is 36.

The square root of 644253363 is about 25382.1465404327. The cubic root of 644253363 is about 863.6787442152.

The spelling of 644253363 in words is "six hundred forty-four million, two hundred fifty-three thousand, three hundred sixty-three".