666999211 has 2 divisors, whose sum is σ = 666999212. Its totient is φ = 666999210.

The previous prime is 666999191. The next prime is 666999227. The reversal of 666999211 is 112999666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666999211 - 2⁷ = 666999083 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (666999611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333499605 + 333499606.

It is an arithmetic number, because the mean of its divisors is an integer number (333499606).

Almost surely, 2^666999211 is an apocalyptic number.

666999211 is a deficient number, since it is larger than the sum of its proper divisors (1).

666999211 is an equidigital number, since it uses as much as digits as its factorization.

666999211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 49.

The square root of 666999211 is about 25826.3278651844. The cubic root of 666999211 is about 873.7256927082.

The spelling of 666999211 in words is "six hundred sixty-six million, nine hundred ninety-nine thousand, two hundred eleven".