668959 has 2 divisors, whose sum is σ = 668960. Its totient is φ = 668958.

The previous prime is 668947. The next prime is 668963. The reversal of 668959 is 959866.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 668959 - 2¹⁹ = 144671 is a prime.

It is a super-2 number, since 2×668959² = 895012287362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668929) 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 as a sum of consecutive naturals, namely, 334479 + 334480.

It is an arithmetic number, because the mean of its divisors is an integer number (334480).

2⁶⁶⁸⁹⁵⁹ is an apocalyptic number.

668959 is a deficient number, since it is larger than the sum of its proper divisors (1).

668959 is an equidigital number, since it uses as much as digits as its factorization.

668959 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 43.

The square root of 668959 is about 817.8991380360. The cubic root of 668959 is about 87.4580588112.

It can be divided in two parts, 66 and 8959, that added together give a square (9025 = 95²).

The spelling of 668959 in words is "six hundred sixty-eight thousand, nine hundred fifty-nine".