644313 has 4 divisors (see below), whose sum is σ = 859088. Its totient is φ = 429540.

The previous prime is 644297. The next prime is 644327. The reversal of 644313 is 313446.

644313 is nontrivially palindromic in base 16.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 644313 - 2⁴ = 644297 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644313.

It is not an unprimeable number, because it can be changed into a prime (644353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107383 + ... + 107388.

It is an arithmetic number, because the mean of its divisors is an integer number (214772).

2⁶⁴⁴³¹³ is an apocalyptic number.

It is an amenable number.

644313 is a deficient number, since it is larger than the sum of its proper divisors (214775).

644313 is a wasteful number, since it uses less digits than its factorization.

644313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214774.

The product of its digits is 864, while the sum is 21.

The square root of 644313 is about 802.6910987422. The cubic root of 644313 is about 86.3705392955.

Adding to 644313 its reverse (313446), we get a palindrome (957759).

The spelling of 644313 in words is "six hundred forty-four thousand, three hundred thirteen".