18042181 has 2 divisors, whose sum is σ = 18042182. Its totient is φ = 18042180.

The previous prime is 18042163. The next prime is 18042197. The reversal of 18042181 is 18124081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9828225 + 8213956 = 3135^2 + 2866^2 .

It is a cyclic number.

It is not a de Polignac number, because 18042181 - 2⁵ = 18042149 is a prime.

It is a super-2 number, since 2×18042181² = 651040590473522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18042121) 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, 9021090 + 9021091.

It is an arithmetic number, because the mean of its divisors is an integer number (9021091).

Almost surely, 2^18042181 is an apocalyptic number.

It is an amenable number.

18042181 is a deficient number, since it is larger than the sum of its proper divisors (1).

18042181 is an equidigital number, since it uses as much as digits as its factorization.

18042181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 512, while the sum is 25.

The square root of 18042181 is about 4247.6088567569. The cubic root of 18042181 is about 262.2786935961.

The spelling of 18042181 in words is "eighteen million, forty-two thousand, one hundred eighty-one".