12111211221 has 16 divisors (see below), whose sum is σ = 16595664000. Its totient is φ = 7850737728.

The previous prime is 12111211201. The next prime is 12111211289. The reversal of 12111211221 is 12211211121.

It is a happy number.

It is not a de Polignac number, because 12111211221 - 2²² = 12107016917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12111211221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12111211201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 136720 + ... + 207158.

It is an arithmetic number, because the mean of its divisors is an integer number (1037229000).

Almost surely, 2^12111211221 is an apocalyptic number.

It is an amenable number.

12111211221 is a deficient number, since it is larger than the sum of its proper divisors (4484452779).

12111211221 is a wasteful number, since it uses less digits than its factorization.

12111211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72028.

The product of its digits is 16, while the sum is 15.

Adding to 12111211221 its reverse (12211211121), we get a palindrome (24322422342).

It can be divided in two parts, 1211121 and 1221, that multiplied together give a palindrome (1478778741).

The spelling of 12111211221 in words is "twelve billion, one hundred eleven million, two hundred eleven thousand, two hundred twenty-one".