668687 has 2 divisors, whose sum is σ = 668688. Its totient is φ = 668686.

The previous prime is 668677. The next prime is 668699. The reversal of 668687 is 786866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 668687 - 2⁴ = 668671 is a prime.

It is a Chen prime.

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 668687.

It is not a weakly prime, because it can be changed into another prime (668617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334343 + 334344.

It is an arithmetic number, because the mean of its divisors is an integer number (334344).

2⁶⁶⁸⁶⁸⁷ is an apocalyptic number.

668687 is a deficient number, since it is larger than the sum of its proper divisors (1).

668687 is an equidigital number, since it uses as much as digits as its factorization.

668687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 41.

The square root of 668687 is about 817.7328414586. The cubic root of 668687 is about 87.4462036667.

The spelling of 668687 in words is "six hundred sixty-eight thousand, six hundred eighty-seven".