12121121221 has 4 divisors (see below), whose sum is σ = 13223041344. Its totient is φ = 11019201100.

The previous prime is 12121121209. The next prime is 12121121273. The reversal of 12121121221 is 12212112121.

12121121221 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 12121121221 - 2⁵ = 12121121189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12121121195 and 12121121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12121121281) 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, 550960045 + ... + 550960066.

It is an arithmetic number, because the mean of its divisors is an integer number (3305760336).

Almost surely, 2^12121121221 is an apocalyptic number.

12121121221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12121121221 is a deficient number, since it is larger than the sum of its proper divisors (1101920123).

12121121221 is a wasteful number, since it uses less digits than its factorization.

12121121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1101920122.

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

Adding to 12121121221 its reverse (12212112121), we get a palindrome (24333233342).

The spelling of 12121121221 in words is "twelve billion, one hundred twenty-one million, one hundred twenty-one thousand, two hundred twenty-one".