12191391 has 20 divisors (see below), whose sum is σ = 18661104. Its totient is φ = 7927200.

The previous prime is 12191381. The next prime is 12191419. The reversal of 12191391 is 19319121.

It is not a de Polignac number, because 12191391 - 2⁶ = 12191327 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12191341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1486 + ... + 5156.

Almost surely, 2^12191391 is an apocalyptic number.

12191391 is a deficient number, since it is larger than the sum of its proper divisors (6469713).

12191391 is an equidigital number, since it uses as much as digits as its factorization.

12191391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3724 (or 3715 counting only the distinct ones).

The product of its digits is 486, while the sum is 27.

The square root of 12191391 is about 3491.6172470647. The cubic root of 12191391 is about 230.1535899141.

The spelling of 12191391 in words is "twelve million, one hundred ninety-one thousand, three hundred ninety-one".