668559 has 8 divisors (see below), whose sum is σ = 943920. Its totient is φ = 419456.

The previous prime is 668543. The next prime is 668567. The reversal of 668559 is 955866.

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 668559 - 2⁴ = 668543 is a prime.

It is a super-2 number, since 2×668559² = 893942272962, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6504 + ... + 6605.

It is an arithmetic number, because the mean of its divisors is an integer number (117990).

2⁶⁶⁸⁵⁵⁹ is an apocalyptic number.

668559 is a deficient number, since it is larger than the sum of its proper divisors (275361).

668559 is a wasteful number, since it uses less digits than its factorization.

668559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13129.

The product of its digits is 64800, while the sum is 39.

The square root of 668559 is about 817.6545725427. The cubic root of 668559 is about 87.4406236627.

The spelling of 668559 in words is "six hundred sixty-eight thousand, five hundred fifty-nine".