644375333 has 12 divisors (see below), whose sum is σ = 753357600. Its totient is φ = 549537912.

The previous prime is 644375317. The next prime is 644375351. The reversal of 644375333 is 333573446.

It is not a de Polignac number, because 644375333 - 2⁴ = 644375317 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 (644375353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23291 + ... + 42792.

It is an arithmetic number, because the mean of its divisors is an integer number (62779800).

Almost surely, 2^644375333 is an apocalyptic number.

It is an amenable number.

644375333 is a deficient number, since it is larger than the sum of its proper divisors (108982267).

644375333 is a wasteful number, since it uses less digits than its factorization.

644375333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66296 (or 66289 counting only the distinct ones).

The product of its digits is 272160, while the sum is 38.

The square root of 644375333 is about 25384.5490997969. The cubic root of 644375333 is about 863.7332446418.

The spelling of 644375333 in words is "six hundred forty-four million, three hundred seventy-five thousand, three hundred thirty-three".