166638317 has 2 divisors, whose sum is σ = 166638318. Its totient is φ = 166638316.

The previous prime is 166638293. The next prime is 166638319. The reversal of 166638317 is 713836661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 154604356 + 12033961 = 12434^2 + 3469^2 .

It is a cyclic number.

It is not a de Polignac number, because 166638317 - 2⁸ = 166638061 is a prime.

Together with 166638319, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166638319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83319158 + 83319159.

It is an arithmetic number, because the mean of its divisors is an integer number (83319159).

Almost surely, 2^166638317 is an apocalyptic number.

It is an amenable number.

166638317 is a deficient number, since it is larger than the sum of its proper divisors (1).

166638317 is an equidigital number, since it uses as much as digits as its factorization.

166638317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 41.

The square root of 166638317 is about 12908.8464627944. The cubic root of 166638317 is about 550.2900035341.

The spelling of 166638317 in words is "one hundred sixty-six million, six hundred thirty-eight thousand, three hundred seventeen".