218191 has 2 divisors, whose sum is σ = 218192. Its totient is φ = 218190.

The previous prime is 218171. The next prime is 218213. The reversal of 218191 is 191812.

It is an a-pointer prime, because the next prime (218213) can be obtained adding 218191 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 218191 - 2¹⁷ = 87119 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109095 + 109096.

It is an arithmetic number, because the mean of its divisors is an integer number (109096).

2²¹⁸¹⁹¹ is an apocalyptic number.

218191 is a deficient number, since it is larger than the sum of its proper divisors (1).

218191 is an equidigital number, since it uses as much as digits as its factorization.

218191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 22.

The square root of 218191 is about 467.1091949427. The cubic root of 218191 is about 60.2021882701.

The spelling of 218191 in words is "two hundred eighteen thousand, one hundred ninety-one".