644789363 has 8 divisors (see below), whose sum is σ = 654097248. Its totient is φ = 635494464.

The previous prime is 644789351. The next prime is 644789399. The reversal of 644789363 is 363987446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644789363 - 2²⁰ = 643740787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644789963) 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 7 ways as a sum of consecutive naturals, for example, 143570 + ... + 147992.

It is an arithmetic number, because the mean of its divisors is an integer number (81762156).

Almost surely, 2^644789363 is an apocalyptic number.

644789363 is a deficient number, since it is larger than the sum of its proper divisors (9307885).

644789363 is a wasteful number, since it uses less digits than its factorization.

644789363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6493.

The product of its digits is 2612736, while the sum is 50.

The square root of 644789363 is about 25392.7029478943. The cubic root of 644789363 is about 863.9181963267.

The spelling of 644789363 in words is "six hundred forty-four million, seven hundred eighty-nine thousand, three hundred sixty-three".