166118261 has 2 divisors, whose sum is σ = 166118262. Its totient is φ = 166118260.

The previous prime is 166118191. The next prime is 166118263. The reversal of 166118261 is 162811661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 100200100 + 65918161 = 10010^2 + 8119^2 .

It is an emirp because it is prime and its reverse (162811661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 166118261 - 2¹⁴ = 166101877 is a prime.

It is a Sophie Germain prime.

Together with 166118263, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166118263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83059130 + 83059131.

It is an arithmetic number, because the mean of its divisors is an integer number (83059131).

Almost surely, 2^166118261 is an apocalyptic number.

It is an amenable number.

166118261 is a deficient number, since it is larger than the sum of its proper divisors (1).

166118261 is an equidigital number, since it uses as much as digits as its factorization.

166118261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 32.

The square root of 166118261 is about 12888.6873264891. The cubic root of 166118261 is about 549.7169463644.

The spelling of 166118261 in words is "one hundred sixty-six million, one hundred eighteen thousand, two hundred sixty-one".