664728 has 16 divisors (see below), whose sum is σ = 1661880. Its totient is φ = 221568.

The previous prime is 664711. The next prime is 664739. The reversal of 664728 is 827466.

It is an Ulam number.

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 664728.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13825 + ... + 13872.

2⁶⁶⁴⁷²⁸ is an apocalyptic number.

It is an amenable number.

664728 is an abundant number, since it is smaller than the sum of its proper divisors (997152).

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

664728 is a wasteful number, since it uses less digits than its factorization.

664728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27706 (or 27702 counting only the distinct ones).

The product of its digits is 16128, while the sum is 33.

The square root of 664728 is about 815.3085305576. The cubic root of 664728 is about 87.2732851921.

The spelling of 664728 in words is "six hundred sixty-four thousand, seven hundred twenty-eight".