644312 has 16 divisors (see below), whose sum is σ = 1236840. Its totient is φ = 314496.

The previous prime is 644297. The next prime is 644327. The reversal of 644312 is 213446.

It is a happy number.

644312 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (644297) and next prime (644327).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644312.

It is an unprimeable number.

644312 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 593 + ... + 1280.

2⁶⁴⁴³¹² is an apocalyptic number.

It is an amenable number.

644312 is a deficient number, since it is larger than the sum of its proper divisors (592528).

644312 is a wasteful number, since it uses less digits than its factorization.

644312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1922 (or 1918 counting only the distinct ones).

The product of its digits is 576, while the sum is 20.

The square root of 644312 is about 802.6904758374. The cubic root of 644312 is about 86.3704946119.

Adding to 644312 its reverse (213446), we get a palindrome (857758).

The spelling of 644312 in words is "six hundred forty-four thousand, three hundred twelve".