644335 has 8 divisors (see below), whose sum is σ = 798336. Its totient is φ = 498720.

The previous prime is 644327. The next prime is 644341. The reversal of 644335 is 533446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 644335 - 2³ = 644327 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1924 + ... + 2233.

It is an arithmetic number, because the mean of its divisors is an integer number (99792).

2⁶⁴⁴³³⁵ is an apocalyptic number.

644335 is a deficient number, since it is larger than the sum of its proper divisors (154001).

644335 is a wasteful number, since it uses less digits than its factorization.

644335 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4193.

The product of its digits is 4320, while the sum is 25.

The square root of 644335 is about 802.7048025271. The cubic root of 644335 is about 86.3715223220.

Subtracting from 644335 its reverse (533446), we obtain a square (110889 = 333²).

It can be divided in two parts, 644 and 335, that added together give a palindrome (979).

The spelling of 644335 in words is "six hundred forty-four thousand, three hundred thirty-five".