166416209 has 2 divisors, whose sum is σ = 166416210. Its totient is φ = 166416208.

The previous prime is 166416191. The next prime is 166416233. The reversal of 166416209 is 902614661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162817600 + 3598609 = 12760^2 + 1897^2 .

It is a cyclic number.

It is not a de Polignac number, because 166416209 - 2¹⁶ = 166350673 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (166416259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83208104 + 83208105.

It is an arithmetic number, because the mean of its divisors is an integer number (83208105).

Almost surely, 2^166416209 is an apocalyptic number.

It is an amenable number.

166416209 is a deficient number, since it is larger than the sum of its proper divisors (1).

166416209 is an equidigital number, since it uses as much as digits as its factorization.

166416209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 166416209 is about 12900.2406566699. The cubic root of 166416209 is about 550.0454056178.

The spelling of 166416209 in words is "one hundred sixty-six million, four hundred sixteen thousand, two hundred nine".