20111111122121 has 4 divisors (see below), whose sum is σ = 20111329915332. Its totient is φ = 20110892328912.

The previous prime is 20111111122061. The next prime is 20111111122163. The reversal of 20111111122121 is 12122111111102.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3377284632121 + 16733826490000 = 1837739^2 + 4090700^2 .

It is a cyclic number.

It is not a de Polignac number, because 20111111122121 - 2⁶ = 20111111122057 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 20111111122121.

It is not an unprimeable number, because it can be changed into a prime (20111111121121) 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, 109258670 + ... + 109442583.

It is an arithmetic number, because the mean of its divisors is an integer number (5027832478833).

Almost surely, 2^{20111111122121} is an apocalyptic number.

It is an amenable number.

20111111122121 is a deficient number, since it is larger than the sum of its proper divisors (218793211).

20111111122121 is an equidigital number, since it uses as much as digits as its factorization.

20111111122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218793210.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 20111111122121 its reverse (12122111111102), we get a palindrome (32233222233223).

The spelling of 20111111122121 in words is "twenty trillion, one hundred eleven billion, one hundred eleven million, one hundred twenty-two thousand, one hundred twenty-one".