6666147209 has 2 divisors, whose sum is σ = 6666147210. Its totient is φ = 6666147208.

The previous prime is 6666147181. The next prime is 6666147211. The reversal of 6666147209 is 9027416666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3969630025 + 2696517184 = 63005^2 + 51928^2 .

It is a cyclic number.

It is not a de Polignac number, because 6666147209 - 2¹⁶ = 6666081673 is a prime.

It is a super-2 number, since 2×6666147209² = 88875037224116979362, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 6666147211, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (6666146209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3333073604 + 3333073605.

It is an arithmetic number, because the mean of its divisors is an integer number (3333073605).

Almost surely, 2^6666147209 is an apocalyptic number.

It is an amenable number.

6666147209 is a deficient number, since it is larger than the sum of its proper divisors (1).

6666147209 is an equidigital number, since it uses as much as digits as its factorization.

6666147209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 653184, while the sum is 47.

The square root of 6666147209 is about 81646.4770152393. The cubic root of 6666147209 is about 1882.0231736544.

The spelling of 6666147209 in words is "six billion, six hundred sixty-six million, one hundred forty-seven thousand, two hundred nine".