12165921 has 24 divisors (see below), whose sum is σ = 18120960. Its totient is φ = 7862400.

The previous prime is 12165917. The next prime is 12165929. The reversal of 12165921 is 12956121.

12165921 is a `hidden beast` number, since 1 + 2 + 1 + 659 + 2 + 1 = 666.

12165921 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12165921 - 2² = 12165917 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12165929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 50361 + ... + 50601.

It is an arithmetic number, because the mean of its divisors is an integer number (755040).

Almost surely, 2^12165921 is an apocalyptic number.

It is an amenable number.

12165921 is a deficient number, since it is larger than the sum of its proper divisors (5955039).

12165921 is a wasteful number, since it uses less digits than its factorization.

12165921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397 (or 394 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 12165921 is about 3487.9680331104. The cubic root of 12165921 is about 229.9932008072.

The spelling of 12165921 in words is "twelve million, one hundred sixty-five thousand, nine hundred twenty-one".