166311217 has 2 divisors, whose sum is σ = 166311218. Its totient is φ = 166311216.

The previous prime is 166311209. The next prime is 166311241. The reversal of 166311217 is 712113661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 165791376 + 519841 = 12876^2 + 721^2 .

It is a cyclic number.

It is not a de Polignac number, because 166311217 - 2³ = 166311209 is a prime.

It is not a weakly prime, because it can be changed into another prime (166311517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83155608 + 83155609.

It is an arithmetic number, because the mean of its divisors is an integer number (83155609).

Almost surely, 2^166311217 is an apocalyptic number.

It is an amenable number.

166311217 is a deficient number, since it is larger than the sum of its proper divisors (1).

166311217 is an equidigital number, since it uses as much as digits as its factorization.

166311217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1512, while the sum is 28.

The square root of 166311217 is about 12896.1706331763. The cubic root of 166311217 is about 549.9297067190.

Adding to 166311217 its reverse (712113661), we get a palindrome (878424878).

It can be divided in two parts, 1663 and 11217, that added together give a triangular number (12880 = T₁₆₀).

The spelling of 166311217 in words is "one hundred sixty-six million, three hundred eleven thousand, two hundred seventeen".