12111221221 has 4 divisors (see below), whose sum is σ = 13212241344. Its totient is φ = 11010201100.

The previous prime is 12111221219. The next prime is 12111221231. The reversal of 12111221221 is 12212211121.

12111221221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is not a de Polignac number, because 12111221221 - 2¹ = 12111221219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12111221195 and 12111221204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12111221231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 550510045 + ... + 550510066.

It is an arithmetic number, because the mean of its divisors is an integer number (3303060336).

Almost surely, 2^12111221221 is an apocalyptic number.

12111221221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12111221221 is a deficient number, since it is larger than the sum of its proper divisors (1101020123).

12111221221 is a wasteful number, since it uses less digits than its factorization.

12111221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1101020122.

The product of its digits is 32, while the sum is 16.

Adding to 12111221221 its reverse (12212211121), we get a palindrome (24323432342).

It can be divided in two parts, 12111 and 221221, that added together give a palindrome (233332).

The spelling of 12111221221 in words is "twelve billion, one hundred eleven million, two hundred twenty-one thousand, two hundred twenty-one".