166557317 has 2 divisors, whose sum is σ = 166557318. Its totient is φ = 166557316.

The previous prime is 166557301. The next prime is 166557319. The reversal of 166557317 is 713755661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 141467236 + 25090081 = 11894^2 + 5009^2 .

It is a cyclic number.

It is not a de Polignac number, because 166557317 - 2⁴ = 166557301 is a prime.

Together with 166557319, 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 (166557319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83278658 + 83278659.

It is an arithmetic number, because the mean of its divisors is an integer number (83278659).

Almost surely, 2^166557317 is an apocalyptic number.

It is an amenable number.

166557317 is a deficient number, since it is larger than the sum of its proper divisors (1).

166557317 is an equidigital number, since it uses as much as digits as its factorization.

166557317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 132300, while the sum is 41.

The square root of 166557317 is about 12905.7086980917. The cubic root of 166557317 is about 550.2008269366.

The spelling of 166557317 in words is "one hundred sixty-six million, five hundred fifty-seven thousand, three hundred seventeen".