12391931 has 4 divisors (see below), whose sum is σ = 12406200. Its totient is φ = 12377664.

The previous prime is 12391927. The next prime is 12391937. The reversal of 12391931 is 13919321.

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

It is a cyclic number.

It is not a de Polignac number, because 12391931 - 2² = 12391927 is a prime.

It is a super-2 number, since 2×12391931² = 307119907817522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12391894 and 12391903.

It is not an unprimeable number, because it can be changed into a prime (12391937) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5741 + ... + 7598.

It is an arithmetic number, because the mean of its divisors is an integer number (3101550).

Almost surely, 2^12391931 is an apocalyptic number.

12391931 is a deficient number, since it is larger than the sum of its proper divisors (14269).

12391931 is an equidigital number, since it uses as much as digits as its factorization.

12391931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14268.

The product of its digits is 1458, while the sum is 29.

The square root of 12391931 is about 3520.2174648734. The cubic root of 12391931 is about 231.4086891310.

It can be divided in two parts, 1 and 2391931, that added together give a palindrome (2391932).

The spelling of 12391931 in words is "twelve million, three hundred ninety-one thousand, nine hundred thirty-one".