644444 has 12 divisors (see below), whose sum is σ = 1143744. Its totient is φ = 317664.

The previous prime is 644443. The next prime is 644447. The reversal of 644444 is 444446.

644444 is a modest number, since divided by 4444 gives 64 as remainder.

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 (644443) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 812 + ... + 1395.

It is an arithmetic number, because the mean of its divisors is an integer number (95312).

2⁶⁴⁴⁴⁴⁴ is an apocalyptic number.

It is an amenable number.

644444 is a deficient number, since it is larger than the sum of its proper divisors (499300).

644444 is a wasteful number, since it uses less digits than its factorization.

644444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2284 (or 2282 counting only the distinct ones).

The product of its digits is 6144, while the sum is 26.

The square root of 644444 is about 802.7726951012. The cubic root of 644444 is about 86.3763924413.

The spelling of 644444 in words is "six hundred forty-four thousand, four hundred forty-four".