644335013 has 8 divisors (see below), whose sum is σ = 743975232. Its totient is φ = 546592896.

The previous prime is 644334997. The next prime is 644335019. The reversal of 644335013 is 310533446.

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 644335013 - 2⁴ = 644334997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644335019) 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, 473795 + ... + 475152.

It is an arithmetic number, because the mean of its divisors is an integer number (92996904).

Almost surely, 2^644335013 is an apocalyptic number.

It is an amenable number.

644335013 is a deficient number, since it is larger than the sum of its proper divisors (99640219).

644335013 is an equidigital number, since it uses as much as digits as its factorization.

644335013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 949051.

The product of its (nonzero) digits is 12960, while the sum is 29.

The square root of 644335013 is about 25383.7549034811. The cubic root of 644335013 is about 863.7152290283.

Adding to 644335013 its reverse (310533446), we get a palindrome (954868459).

The spelling of 644335013 in words is "six hundred forty-four million, three hundred thirty-five thousand, thirteen".