668998669 has 2 divisors, whose sum is σ = 668998670. Its totient is φ = 668998668.

The previous prime is 668998657. The next prime is 668998679. The reversal of 668998669 is 966899866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 340845444 + 328153225 = 18462^2 + 18115^2 .

It is a cyclic number.

It is not a de Polignac number, because 668998669 - 2¹⁵ = 668965901 is a prime.

It is a super-2 number, since 2×668998669² = 895118438247543122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668998639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334499334 + 334499335.

It is an arithmetic number, because the mean of its divisors is an integer number (334499335).

Almost surely, 2^668998669 is an apocalyptic number.

It is an amenable number.

668998669 is a deficient number, since it is larger than the sum of its proper divisors (1).

668998669 is an equidigital number, since it uses as much as digits as its factorization.

668998669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60466176, while the sum is 67.

The square root of 668998669 is about 25865.0085830258. The cubic root of 668998669 is about 874.5978751961.

The spelling of 668998669 in words is "six hundred sixty-eight million, nine hundred ninety-eight thousand, six hundred sixty-nine".