668869 has 2 divisors, whose sum is σ = 668870. Its totient is φ = 668868.

The previous prime is 668867. The next prime is 668873. The reversal of 668869 is 968866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 656100 + 12769 = 810^2 + 113^2 .

It is a cyclic number.

It is not a de Polignac number, because 668869 - 2¹ = 668867 is a prime.

It is a super-2 number, since 2×668869² = 894771478322, which contains 22 as substring.

Together with 668867, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334434 + 334435.

It is an arithmetic number, because the mean of its divisors is an integer number (334435).

2⁶⁶⁸⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

668869 is a deficient number, since it is larger than the sum of its proper divisors (1).

668869 is an equidigital number, since it uses as much as digits as its factorization.

668869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 43.

The square root of 668869 is about 817.8441171764. The cubic root of 668869 is about 87.4541365089.

The spelling of 668869 in words is "six hundred sixty-eight thousand, eight hundred sixty-nine".