644864303 has 8 divisors (see below), whose sum is σ = 659793600. Its totient is φ = 630037408.

The previous prime is 644864293. The next prime is 644864309. The reversal of 644864303 is 303468446.

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 644864303 - 2¹⁰ = 644863279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644864309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12788 + ... + 38121.

It is an arithmetic number, because the mean of its divisors is an integer number (82474200).

Almost surely, 2^644864303 is an apocalyptic number.

644864303 is a deficient number, since it is larger than the sum of its proper divisors (14929297).

644864303 is a wasteful number, since it uses less digits than its factorization.

644864303 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51201.

The product of its (nonzero) digits is 165888, while the sum is 38.

The square root of 644864303 is about 25394.1785257960. The cubic root of 644864303 is about 863.9516643734.

The spelling of 644864303 in words is "six hundred forty-four million, eight hundred sixty-four thousand, three hundred three".