644338 has 4 divisors (see below), whose sum is σ = 966510. Its totient is φ = 322168.

The previous prime is 644327. The next prime is 644341. The reversal of 644338 is 833446.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 573049 + 71289 = 757^2 + 267^2 .

It is a d-powerful number, because it can be written as 6⁵ + 4⁴ + 3⁸ + 4⁸ + 3¹² + 8⁵ .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 161083 + ... + 161086.

2⁶⁴⁴³³⁸ is an apocalyptic number.

644338 is a deficient number, since it is larger than the sum of its proper divisors (322172).

644338 is a wasteful number, since it uses less digits than its factorization.

644338 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322171.

The product of its digits is 6912, while the sum is 28.

The square root of 644338 is about 802.7066712069. The cubic root of 644338 is about 86.3716563693.

It can be divided in two parts, 6 and 44338, that added together give a palindrome (44344).

The spelling of 644338 in words is "six hundred forty-four thousand, three hundred thirty-eight".