168605209 has 2 divisors, whose sum is σ = 168605210. Its totient is φ = 168605208.

The previous prime is 168605207. The next prime is 168605219. The reversal of 168605209 is 902506861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 92217609 + 76387600 = 9603^2 + 8740^2 .

It is a cyclic number.

It is not a de Polignac number, because 168605209 - 2¹ = 168605207 is a prime.

Together with 168605207, 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 (168605207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84302604 + 84302605.

It is an arithmetic number, because the mean of its divisors is an integer number (84302605).

Almost surely, 2^168605209 is an apocalyptic number.

It is an amenable number.

168605209 is a deficient number, since it is larger than the sum of its proper divisors (1).

168605209 is an equidigital number, since it uses as much as digits as its factorization.

168605209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 168605209 is about 12984.8068526259. The cubic root of 168605209 is about 552.4466307997.

The spelling of 168605209 in words is "one hundred sixty-eight million, six hundred five thousand, two hundred nine".