18228191 has 2 divisors, whose sum is σ = 18228192. Its totient is φ = 18228190.

The previous prime is 18228157. The next prime is 18228209. The reversal of 18228191 is 19182281.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18228191 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 (18224191) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9114095 + 9114096.

It is an arithmetic number, because the mean of its divisors is an integer number (9114096).

Almost surely, 2^18228191 is an apocalyptic number.

18228191 is a deficient number, since it is larger than the sum of its proper divisors (1).

18228191 is an equidigital number, since it uses as much as digits as its factorization.

18228191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 32.

The square root of 18228191 is about 4269.4485592404. The cubic root of 18228191 is about 263.1769544574.

The spelling of 18228191 in words is "eighteen million, two hundred twenty-eight thousand, one hundred ninety-one".