644311 has 4 divisors (see below), whose sum is σ = 649152. Its totient is φ = 639472.

The previous prime is 644297. The next prime is 644327. The reversal of 644311 is 113446.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 644311 - 2¹⁵ = 611543 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2215 + ... + 2488.

It is an arithmetic number, because the mean of its divisors is an integer number (162288).

2⁶⁴⁴³¹¹ is an apocalyptic number.

644311 is a deficient number, since it is larger than the sum of its proper divisors (4841).

644311 is a wasteful number, since it uses less digits than its factorization.

644311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4840.

The product of its digits is 288, while the sum is 19.

The square root of 644311 is about 802.6898529320. The cubic root of 644311 is about 86.3704499283.

Adding to 644311 its reverse (113446), we get a palindrome (757757).

The spelling of 644311 in words is "six hundred forty-four thousand, three hundred eleven".