12138865 has 4 divisors (see below), whose sum is σ = 14566644. Its totient is φ = 9711088.

The previous prime is 12138851. The next prime is 12138869. The reversal of 12138865 is 56883121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56883121 = 3851 ⋅14771.

It can be written as a sum of positive squares in 2 ways, for example, as 6190144 + 5948721 = 2488^2 + 2439^2 .

It is a cyclic number.

It is not a de Polignac number, because 12138865 - 2⁹ = 12138353 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12138865.

It is not an unprimeable number, because it can be changed into a prime (12138869) by changing a digit.

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, 1213882 + ... + 1213891.

It is an arithmetic number, because the mean of its divisors is an integer number (3641661).

Almost surely, 2^12138865 is an apocalyptic number.

It is an amenable number.

12138865 is a deficient number, since it is larger than the sum of its proper divisors (2427779).

12138865 is an equidigital number, since it uses as much as digits as its factorization.

12138865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2427778.

The product of its digits is 11520, while the sum is 34.

The square root of 12138865 is about 3484.0873984445. The cubic root of 12138865 is about 229.8225789894.

The spelling of 12138865 in words is "twelve million, one hundred thirty-eight thousand, eight hundred sixty-five".