12391 has 2 divisors, whose sum is σ = 12392. Its totient is φ = 12390.

The previous prime is 12379. The next prime is 12401. The reversal of 12391 is 19321.

12391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 12391 - 2⁷ = 12263 is a prime.

12391 is a lucky number.

It is a zygodrome in base 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6195 + 6196.

It is an arithmetic number, because the mean of its divisors is an integer number (6196).

2¹²³⁹¹ is an apocalyptic number.

12391 is the 60-th centered heptagonal number.

12391 is a deficient number, since it is larger than the sum of its proper divisors (1).

12391 is an equidigital number, since it uses as much as digits as its factorization.

12391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54, while the sum is 16.

The square root of 12391 is about 111.3148687283. The cubic root of 12391 is about 23.1402893777.

The spelling of 12391 in words is "twelve thousand, three hundred ninety-one".