18042161 has 2 divisors, whose sum is σ = 18042162. Its totient is φ = 18042160.

The previous prime is 18042149. The next prime is 18042163. The reversal of 18042161 is 16124081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18011536 + 30625 = 4244^2 + 175^2 .

It is a cyclic number.

It is not a de Polignac number, because 18042161 - 2²² = 13847857 is a prime.

Together with 18042163, 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 (18042163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9021080 + 9021081.

It is an arithmetic number, because the mean of its divisors is an integer number (9021081).

Almost surely, 2^18042161 is an apocalyptic number.

It is an amenable number.

18042161 is a deficient number, since it is larger than the sum of its proper divisors (1).

18042161 is an equidigital number, since it uses as much as digits as its factorization.

18042161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 18042161 is about 4247.6065024905. The cubic root of 18042161 is about 262.2785966829.

The spelling of 18042161 in words is "eighteen million, forty-two thousand, one hundred sixty-one".