669906817 has 2 divisors, whose sum is σ = 669906818. Its totient is φ = 669906816.

The previous prime is 669906799. The next prime is 669906821. The reversal of 669906817 is 718609966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 669826161 + 80656 = 25881^2 + 284^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-669906817 is a prime.

It is not a weakly prime, because it can be changed into another prime (669906877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334953408 + 334953409.

It is an arithmetic number, because the mean of its divisors is an integer number (334953409).

Almost surely, 2^669906817 is an apocalyptic number.

It is an amenable number.

669906817 is a deficient number, since it is larger than the sum of its proper divisors (1).

669906817 is an equidigital number, since it uses as much as digits as its factorization.

669906817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 979776, while the sum is 52.

The square root of 669906817 is about 25882.5581618201. The cubic root of 669906817 is about 874.9934440869.

The spelling of 669906817 in words is "six hundred sixty-nine million, nine hundred six thousand, eight hundred seventeen".