18122191 has 2 divisors, whose sum is σ = 18122192. Its totient is φ = 18122190.

The previous prime is 18122179. The next prime is 18122201. The reversal of 18122191 is 19122181.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18122191 - 2¹¹ = 18120143 is a prime.

It is equal to p_1158604 and since 18122191 and 1158604 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18122101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9061095 + 9061096.

It is an arithmetic number, because the mean of its divisors is an integer number (9061096).

Almost surely, 2^18122191 is an apocalyptic number.

18122191 is a deficient number, since it is larger than the sum of its proper divisors (1).

18122191 is an equidigital number, since it uses as much as digits as its factorization.

18122191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 25.

The square root of 18122191 is about 4257.0166783794. The cubic root of 18122191 is about 262.6658229665.

The spelling of 18122191 in words is "eighteen million, one hundred twenty-two thousand, one hundred ninety-one".