666668890999 has 2 divisors, whose sum is σ = 666668891000. Its totient is φ = 666668890998.

The previous prime is 666668890969. The next prime is 666668891027. The reversal of 666668890999 is 999098866666.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666668890999 - 2¹⁷ = 666668759927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666668890969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333334445499 + 333334445500.

It is an arithmetic number, because the mean of its divisors is an integer number (333334445500).

Almost surely, 2^666668890999 is an apocalyptic number.

666668890999 is a deficient number, since it is larger than the sum of its proper divisors (1).

666668890999 is an equidigital number, since it uses as much as digits as its factorization.

666668890999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3265173504, while the sum is 82.

The spelling of 666668890999 in words is "six hundred sixty-six billion, six hundred sixty-eight million, eight hundred ninety thousand, nine hundred ninety-nine".