644255313 has 8 divisors (see below), whose sum is σ = 925084608. Its totient is φ = 396464784.

The previous prime is 644255281. The next prime is 644255347. The reversal of 644255313 is 313552446.

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

It is not a de Polignac number, because 644255313 - 2⁵ = 644255281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644255383) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8259645 + ... + 8259722.

It is an arithmetic number, because the mean of its divisors is an integer number (115635576).

Almost surely, 2^644255313 is an apocalyptic number.

It is an amenable number.

644255313 is a deficient number, since it is larger than the sum of its proper divisors (280829295).

644255313 is a wasteful number, since it uses less digits than its factorization.

644255313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16519383.

The product of its digits is 43200, while the sum is 33.

The square root of 644255313 is about 25382.1849532305. The cubic root of 644255313 is about 863.6796155970.

The spelling of 644255313 in words is "six hundred forty-four million, two hundred fifty-five thousand, three hundred thirteen".