644339 has 8 divisors (see below), whose sum is σ = 669120. Its totient is φ = 620136.

The previous prime is 644327. The next prime is 644341. The reversal of 644339 is 933446.

It is a happy number.

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 644339 - 2¹⁶ = 578803 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644359) 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, 3872 + ... + 4034.

It is an arithmetic number, because the mean of its divisors is an integer number (83640).

2⁶⁴⁴³³⁹ is an apocalyptic number.

644339 is a deficient number, since it is larger than the sum of its proper divisors (24781).

644339 is a wasteful number, since it uses less digits than its factorization.

644339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289.

The product of its digits is 7776, while the sum is 29.

The square root of 644339 is about 802.7072940992. The cubic root of 644339 is about 86.3717010516.

The spelling of 644339 in words is "six hundred forty-four thousand, three hundred thirty-nine".