664659 has 16 divisors (see below), whose sum is σ = 998400. Its totient is φ = 436968.

The previous prime is 664633. The next prime is 664661. The reversal of 664659 is 956466.

It is a happy number.

664659 is a `hidden beast` number, since 6 + 646 + 5 + 9 = 666.

It is not a de Polignac number, because 664659 - 2⁸ = 664403 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (664619) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2662 + ... + 2900.

It is an arithmetic number, because the mean of its divisors is an integer number (62400).

2⁶⁶⁴⁶⁵⁹ is an apocalyptic number.

664659 is a deficient number, since it is larger than the sum of its proper divisors (333741).

664659 is a wasteful number, since it uses less digits than its factorization.

664659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351 (or 345 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 664659 is about 815.2662141902. The cubic root of 664659 is about 87.2702653780.

The spelling of 664659 in words is "six hundred sixty-four thousand, six hundred fifty-nine".