12165856121 has 4 divisors (see below), whose sum is σ = 12286310244. Its totient is φ = 12045402000.

The previous prime is 12165856117. The next prime is 12165856127.

12165856121 is nontrivially palindromic in base 10.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8549036521 + 3616819600 = 92461^2 + 60140^2 .

It is a cyclic number.

It is not a de Polignac number, because 12165856121 - 2² = 12165856117 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12165856127) 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, 60226910 + ... + 60227111.

It is an arithmetic number, because the mean of its divisors is an integer number (3071577561).

Almost surely, 2^12165856121 is an apocalyptic number.

It is an amenable number.

12165856121 is a deficient number, since it is larger than the sum of its proper divisors (120454123).

12165856121 is a wasteful number, since it uses less digits than its factorization.

12165856121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120454122.

The product of its digits is 28800, while the sum is 38.

The spelling of 12165856121 in words is "twelve billion, one hundred sixty-five million, eight hundred fifty-six thousand, one hundred twenty-one".