181666117 has 2 divisors, whose sum is σ = 181666118. Its totient is φ = 181666116.

The previous prime is 181666081. The next prime is 181666123. The reversal of 181666117 is 711666181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 175668516 + 5997601 = 13254^2 + 2449^2 .

It is an emirp because it is prime and its reverse (711666181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181666117 - 2²³ = 173277509 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181666127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90833058 + 90833059.

It is an arithmetic number, because the mean of its divisors is an integer number (90833059).

Almost surely, 2^181666117 is an apocalyptic number.

It is an amenable number.

181666117 is a deficient number, since it is larger than the sum of its proper divisors (1).

181666117 is an equidigital number, since it uses as much as digits as its factorization.

181666117 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 37.

The square root of 181666117 is about 13478.3573554050. The cubic root of 181666117 is about 566.3583543521.

The spelling of 181666117 in words is "one hundred eighty-one million, six hundred sixty-six thousand, one hundred seventeen".