668859 has 4 divisors (see below), whose sum is σ = 891816. Its totient is φ = 445904.

The previous prime is 668851. The next prime is 668867. The reversal of 668859 is 958866.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (668851) and next prime (668867).

It is a cyclic number.

It is not a de Polignac number, because 668859 - 2³ = 668851 is a prime.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 668859.

It is not an unprimeable number, because it can be changed into a prime (668851) 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 3 ways as a sum of consecutive naturals, for example, 111474 + ... + 111479.

It is an arithmetic number, because the mean of its divisors is an integer number (222954).

2⁶⁶⁸⁸⁵⁹ is an apocalyptic number.

668859 is a deficient number, since it is larger than the sum of its proper divisors (222957).

668859 is a wasteful number, since it uses less digits than its factorization.

668859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222956.

The product of its digits is 103680, while the sum is 42.

The square root of 668859 is about 817.8380035190. The cubic root of 668859 is about 87.4537006758.

The spelling of 668859 in words is "six hundred sixty-eight thousand, eight hundred fifty-nine".