12191 has 4 divisors (see below), whose sum is σ = 12432. Its totient is φ = 11952.

The previous prime is 12163. The next prime is 12197. The reversal of 12191 is 19121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12191 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12197) 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 in 3 ways as a sum of consecutive naturals, for example, 11 + ... + 156.

It is an arithmetic number, because the mean of its divisors is an integer number (3108).

2¹²¹⁹¹ is an apocalyptic number.

12191 is a deficient number, since it is larger than the sum of its proper divisors (241).

12191 is an equidigital number, since it uses as much as digits as its factorization.

12191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240.

The product of its digits is 18, while the sum is 14.

The square root of 12191 is about 110.4128615697. The cubic root of 12191 is about 23.0151129407.

It can be divided in two parts, 121 and 91, that multiplied together give a palindrome (11011).

The spelling of 12191 in words is "twelve thousand, one hundred ninety-one".