644344 has 16 divisors (see below), whose sum is σ = 1216800. Its totient is φ = 319872.

The previous prime is 644341. The next prime is 644353. The reversal of 644344 is 443446.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644341) 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, 1744 + ... + 2080.

It is an arithmetic number, because the mean of its divisors is an integer number (76050).

2⁶⁴⁴³⁴⁴ is an apocalyptic number.

It is an amenable number.

644344 is a deficient number, since it is larger than the sum of its proper divisors (572456).

644344 is a wasteful number, since it uses less digits than its factorization.

644344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582 (or 578 counting only the distinct ones).

The product of its digits is 4608, while the sum is 25.

The square root of 644344 is about 802.7104085534. The cubic root of 644344 is about 86.3719244627.

The spelling of 644344 in words is "six hundred forty-four thousand, three hundred forty-four".