12221211221 has 4 divisors (see below), whose sum is σ = 12236281344. Its totient is φ = 12206141100.

The previous prime is 12221211203. The next prime is 12221211227. The reversal of 12221211221 is 12211212221.

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: 12211212221 = 13 ⋅939324017.

It is a cyclic number.

It is not a de Polignac number, because 12221211221 - 2²⁶ = 12154102357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 12221211221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12221211227) 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, 7533845 + ... + 7535466.

It is an arithmetic number, because the mean of its divisors is an integer number (3059070336).

Almost surely, 2^12221211221 is an apocalyptic number.

It is an amenable number.

12221211221 is a deficient number, since it is larger than the sum of its proper divisors (15070123).

12221211221 is an equidigital number, since it uses as much as digits as its factorization.

12221211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15070122.

The product of its digits is 64, while the sum is 17.

Adding to 12221211221 its reverse (12211212221), we get a palindrome (24432423442).

The spelling of 12221211221 in words is "twelve billion, two hundred twenty-one million, two hundred eleven thousand, two hundred twenty-one".