664559 has 8 divisors (see below), whose sum is σ = 766080. Its totient is φ = 564696.

The previous prime is 664549. The next prime is 664561. The reversal of 664559 is 955466.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 664559 - 2¹⁶ = 599023 is a prime.

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 664559.

It is not an unprimeable number, because it can be changed into a prime (664529) 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, 632 + ... + 1314.

It is an arithmetic number, because the mean of its divisors is an integer number (95760).

2⁶⁶⁴⁵⁵⁹ is an apocalyptic number.

664559 is a deficient number, since it is larger than the sum of its proper divisors (101521).

664559 is a wasteful number, since it uses less digits than its factorization.

664559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 829.

The product of its digits is 32400, while the sum is 35.

The square root of 664559 is about 815.2048822229. The cubic root of 664559 is about 87.2658884648.

It can be divided in two parts, 6645 and 59, that multiplied together give a triangular number (392055 = T₈₈₅).

The spelling of 664559 in words is "six hundred sixty-four thousand, five hundred fifty-nine".