668676917 has 2 divisors, whose sum is σ = 668676918. Its totient is φ = 668676916.

The previous prime is 668676859. The next prime is 668676989. The reversal of 668676917 is 719676866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 388917841 + 279759076 = 19721^2 + 16726^2 .

It is a cyclic number.

It is not a de Polignac number, because 668676917 - 2¹⁰ = 668675893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668676017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334338458 + 334338459.

It is an arithmetic number, because the mean of its divisors is an integer number (334338459).

Almost surely, 2^668676917 is an apocalyptic number.

It is an amenable number.

668676917 is a deficient number, since it is larger than the sum of its proper divisors (1).

668676917 is an equidigital number, since it uses as much as digits as its factorization.

668676917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4572288, while the sum is 56.

The square root of 668676917 is about 25858.7880033075. The cubic root of 668676917 is about 874.4576413641.

The spelling of 668676917 in words is "six hundred sixty-eight million, six hundred seventy-six thousand, nine hundred seventeen".