12115891 has 4 divisors (see below), whose sum is σ = 12150000. Its totient is φ = 12081784.

The previous prime is 12115889. The next prime is 12115903. The reversal of 12115891 is 19851121.

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 12115891 - 2¹ = 12115889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12115861) 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, 16516 + ... + 17233.

It is an arithmetic number, because the mean of its divisors is an integer number (3037500).

Almost surely, 2^12115891 is an apocalyptic number.

12115891 is a deficient number, since it is larger than the sum of its proper divisors (34109).

12115891 is an equidigital number, since it uses as much as digits as its factorization.

12115891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34108.

The product of its digits is 720, while the sum is 28.

The square root of 12115891 is about 3480.7888473735. The cubic root of 12115891 is about 229.6775001215.

The spelling of 12115891 in words is "twelve million, one hundred fifteen thousand, eight hundred ninety-one".