12115105521 has 4 divisors (see below), whose sum is σ = 16153474032. Its totient is φ = 8076737012.

The previous prime is 12115105493. The next prime is 12115105529. The reversal of 12115105521 is 12550151121.

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: 12550151121 = 3 ⋅4183383707.

It is a cyclic number.

It is not a de Polignac number, because 12115105521 - 2¹⁰ = 12115104497 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 12115105491 and 12115105500.

It is not an unprimeable number, because it can be changed into a prime (12115105529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2019184251 + ... + 2019184256.

It is an arithmetic number, because the mean of its divisors is an integer number (4038368508).

Almost surely, 2^12115105521 is an apocalyptic number.

It is an amenable number.

12115105521 is a deficient number, since it is larger than the sum of its proper divisors (4038368511).

12115105521 is an equidigital number, since it uses as much as digits as its factorization.

12115105521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4038368510.

The product of its (nonzero) digits is 500, while the sum is 24.

Adding to 12115105521 its reverse (12550151121), we get a palindrome (24665256642).

The spelling of 12115105521 in words is "twelve billion, one hundred fifteen million, one hundred five thousand, five hundred twenty-one".