166543217 has 2 divisors, whose sum is σ = 166543218. Its totient is φ = 166543216.

The previous prime is 166543193. The next prime is 166543219. The reversal of 166543217 is 712345661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 153983281 + 12559936 = 12409^2 + 3544^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166543217 is a prime.

Together with 166543219, 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 (166543219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83271608 + 83271609.

It is an arithmetic number, because the mean of its divisors is an integer number (83271609).

Almost surely, 2^166543217 is an apocalyptic number.

It is an amenable number.

166543217 is a deficient number, since it is larger than the sum of its proper divisors (1).

166543217 is an equidigital number, since it uses as much as digits as its factorization.

166543217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 35.

The square root of 166543217 is about 12905.1624166455. The cubic root of 166543217 is about 550.1853006487.

Adding to 166543217 its reverse (712345661), we get a palindrome (878888878).

The spelling of 166543217 in words is "one hundred sixty-six million, five hundred forty-three thousand, two hundred seventeen".