12123391 has 4 divisors (see below), whose sum is σ = 13855312. Its totient is φ = 10391472.

The previous prime is 12123373. The next prime is 12123439. The reversal of 12123391 is 19332121.

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

It is not a de Polignac number, because 12123391 - 2⁵ = 12123359 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 (12123341) 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, 865950 + ... + 865963.

It is an arithmetic number, because the mean of its divisors is an integer number (3463828).

Almost surely, 2^12123391 is an apocalyptic number.

12123391 is a deficient number, since it is larger than the sum of its proper divisors (1731921).

12123391 is an equidigital number, since it uses as much as digits as its factorization.

12123391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1731920.

The product of its digits is 324, while the sum is 22.

The square root of 12123391 is about 3481.8660226953. The cubic root of 12123391 is about 229.7248821351.

The spelling of 12123391 in words is "twelve million, one hundred twenty-three thousand, three hundred ninety-one".