12111121221 has 4 divisors (see below), whose sum is σ = 16148161632. Its totient is φ = 8074080812.

The previous prime is 12111121207. The next prime is 12111121223. The reversal of 12111121221 is 12212111121.

It is a happy number.

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 12111121221 - 2⁹ = 12111120709 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12111121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12111121223) 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, 2018520201 + ... + 2018520206.

It is an arithmetic number, because the mean of its divisors is an integer number (4037040408).

Almost surely, 2^12111121221 is an apocalyptic number.

It is an amenable number.

12111121221 is a deficient number, since it is larger than the sum of its proper divisors (4037040411).

12111121221 is an equidigital number, since it uses as much as digits as its factorization.

12111121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4037040410.

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

Adding to 12111121221 its reverse (12212111121), we get a palindrome (24323232342).

The spelling of 12111121221 in words is "twelve billion, one hundred eleven million, one hundred twenty-one thousand, two hundred twenty-one".