644433 has 4 divisors (see below), whose sum is σ = 859248. Its totient is φ = 429620.

The previous prime is 644431. The next prime is 644443. The reversal of 644433 is 334446.

644433 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644433 - 2¹ = 644431 is a prime.

It is a D-number.

644433 is a lucky number.

It is a plaindrome in base 14.

It is a nialpdrome in base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644433.

It is not an unprimeable number, because it can be changed into a prime (644431) 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, 107403 + ... + 107408.

It is an arithmetic number, because the mean of its divisors is an integer number (214812).

2⁶⁴⁴⁴³³ is an apocalyptic number.

It is an amenable number.

644433 is a deficient number, since it is larger than the sum of its proper divisors (214815).

644433 is a wasteful number, since it uses less digits than its factorization.

644433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214814.

The product of its digits is 3456, while the sum is 24.

The square root of 644433 is about 802.7658438175. The cubic root of 644433 is about 86.3759009863.

Adding to 644433 its reverse (334446), we get a palindrome (978879).

It can be divided in two parts, 64443 and 3, that added together give a palindrome (64446).

The spelling of 644433 in words is "six hundred forty-four thousand, four hundred thirty-three".