20121220112111 has 4 divisors (see below), whose sum is σ = 20143904690352. Its totient is φ = 20098535533872.

The previous prime is 20121220112087. The next prime is 20121220112137. The reversal of 20121220112111 is 11121102212102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20121220112111 - 2¹⁸ = 20121219849967 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20121220112111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121220112911) 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, 11342287790 + ... + 11342289563.

It is an arithmetic number, because the mean of its divisors is an integer number (5035976172588).

Almost surely, 2^{20121220112111} is an apocalyptic number.

20121220112111 is a deficient number, since it is larger than the sum of its proper divisors (22684578241).

20121220112111 is an equidigital number, since it uses as much as digits as its factorization.

20121220112111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22684578240.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 20121220112111 its reverse (11121102212102), we get a palindrome (31242322324213).

The spelling of 20121220112111 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty million, one hundred twelve thousand, one hundred eleven".