664944 has 40 divisors (see below), whose sum is σ = 1964160. Its totient is φ = 189888.

The previous prime is 664933. The next prime is 664949. The reversal of 664944 is 449466.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664944.

It is not an unprimeable number, because it can be changed into a prime (664949) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 654 + ... + 1325.

It is an arithmetic number, because the mean of its divisors is an integer number (49104).

2⁶⁶⁴⁹⁴⁴ is an apocalyptic number.

It is an amenable number.

664944 is an abundant number, since it is smaller than the sum of its proper divisors (1299216).

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

664944 is a wasteful number, since it uses less digits than its factorization.

664944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1997 (or 1991 counting only the distinct ones).

The product of its digits is 20736, while the sum is 33.

The square root of 664944 is about 815.4409849891. The cubic root of 664944 is about 87.2827371726.

The spelling of 664944 in words is "six hundred sixty-four thousand, nine hundred forty-four".