644012363 has 4 divisors (see below), whose sum is σ = 644990280. Its totient is φ = 643034448.

The previous prime is 644012323. The next prime is 644012371. The reversal of 644012363 is 363210446.

644012363 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 644012363 - 2²⁰ = 642963787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644012323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 487970 + ... + 489287.

It is an arithmetic number, because the mean of its divisors is an integer number (161247570).

Almost surely, 2^644012363 is an apocalyptic number.

644012363 is a deficient number, since it is larger than the sum of its proper divisors (977917).

644012363 is an equidigital number, since it uses as much as digits as its factorization.

644012363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 977916.

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 644012363 is about 25377.3986649538. The cubic root of 644012363 is about 863.5710368292.

The spelling of 644012363 in words is "six hundred forty-four million, twelve thousand, three hundred sixty-three".