66666000209 has 2 divisors, whose sum is σ = 66666000210. Its totient is φ = 66666000208.

The previous prime is 66666000199. The next prime is 66666000211. The reversal of 66666000209 is 90200066666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44495683600 + 22170316609 = 210940^2 + 148897^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66666000209 is a prime.

Together with 66666000211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66666000299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33333000104 + 33333000105.

It is an arithmetic number, because the mean of its divisors is an integer number (33333000105).

Almost surely, 2^66666000209 is an apocalyptic number.

It is an amenable number.

66666000209 is a deficient number, since it is larger than the sum of its proper divisors (1).

66666000209 is an equidigital number, since it uses as much as digits as its factorization.

66666000209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 41.

The spelling of 66666000209 in words is "sixty-six billion, six hundred sixty-six million, two hundred nine", and thus it is an aban number.