12393921 has 4 divisors (see below), whose sum is σ = 16525232. Its totient is φ = 8262612.

The previous prime is 12393889. The next prime is 12393923. The reversal of 12393921 is 12939321.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12939321 = 3 ⋅4313107.

It is not a de Polignac number, because 12393921 - 2⁵ = 12393889 is a prime.

It is the 3521-st Hogben number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12393923) by changing a digit.

It is a nontrivial repunit in base 3520.

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 3 ways as a sum of consecutive naturals, for example, 2065651 + ... + 2065656.

It is an arithmetic number, because the mean of its divisors is an integer number (4131308).

Almost surely, 2^12393921 is an apocalyptic number.

It is an amenable number.

12393921 is a deficient number, since it is larger than the sum of its proper divisors (4131311).

12393921 is an equidigital number, since it uses as much as digits as its factorization.

12393921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4131310.

The product of its digits is 2916, while the sum is 30.

The square root of 12393921 is about 3520.5001065190. The cubic root of 12393921 is about 231.4210756494.

The spelling of 12393921 in words is "twelve million, three hundred ninety-three thousand, nine hundred twenty-one".