6444 has 18 divisors (see below), whose sum is σ = 16380. Its totient is φ = 2136.

The previous prime is 6427. The next prime is 6449. The reversal of 6444 is 4446.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a nialpdrome in base 9 and base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 6444.

It is not an unprimeable number, because it can be changed into a prime (6449) 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, 54 + ... + 125.

It is an arithmetic number, because the mean of its divisors is an integer number (910).

2⁶⁴⁴⁴ is an apocalyptic number.

It is an amenable number.

6444 is an abundant number, since it is smaller than the sum of its proper divisors (9936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6444 is a wasteful number, since it uses less digits than its factorization.

6444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189 (or 184 counting only the distinct ones).

The product of its digits is 384, while the sum is 18.

The square root of 6444 is about 80.2745289616. The cubic root of 6444 is about 18.6088060972.

The spelling of 6444 in words is "six thousand, four hundred forty-four".