664988 has 6 divisors (see below), whose sum is σ = 1163736. Its totient is φ = 332492.

The previous prime is 664973. The next prime is 664997. The reversal of 664988 is 889466.

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 664988.

It is an unprimeable number.

664988 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83120 + ... + 83127.

It is an arithmetic number, because the mean of its divisors is an integer number (193956).

2⁶⁶⁴⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

664988 is a deficient number, since it is larger than the sum of its proper divisors (498748).

664988 is a wasteful number, since it uses less digits than its factorization.

664988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166251 (or 166249 counting only the distinct ones).

The product of its digits is 82944, while the sum is 41.

The square root of 664988 is about 815.4679638097. The cubic root of 664988 is about 87.2846623250.

The spelling of 664988 in words is "six hundred sixty-four thousand, nine hundred eighty-eight".