644204 has 18 divisors (see below), whose sum is σ = 1240092. Its totient is φ = 292820.

The previous prime is 644201. The next prime is 644227. The reversal of 644204 is 402446.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

644204 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nialpdrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (644201) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 58559 + ... + 58569.

It is an arithmetic number, because the mean of its divisors is an integer number (68894).

2⁶⁴⁴²⁰⁴ is an apocalyptic number.

It is an amenable number.

644204 is a deficient number, since it is larger than the sum of its proper divisors (595888).

644204 is an frugal number, since it uses more digits than its factorization.

644204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59 (or 13 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 644204 is about 802.6231992660. The cubic root of 644204 is about 86.3656685159.

It can be divided in two parts, 644 and 204, that added together give a palindrome (848).

The spelling of 644204 in words is "six hundred forty-four thousand, two hundred four".