21220111112121 has 12 divisors (see below), whose sum is σ = 30954749544420. Its totient is φ = 14006674000800.

The previous prime is 21220111112119. The next prime is 21220111112129. The reversal of 21220111112121 is 12121111102212.

It is a happy number.

21220111112121 is a `hidden beast` number, since 212 + 201 + 111 + 121 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20760780960000 + 459330152121 = 4556400^2 + 677739^2 .

It is not a de Polignac number, because 21220111112121 - 2¹ = 21220111112119 is a prime.

It is a super-2 number, since 2×21220111112121² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21220111112094 and 21220111112103.

It is not an unprimeable number, because it can be changed into a prime (21220111112129) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11672227426 + ... + 11672229243.

It is an arithmetic number, because the mean of its divisors is an integer number (2579562462035).

Almost surely, 2^{21220111112121} is an apocalyptic number.

It is an amenable number.

21220111112121 is a deficient number, since it is larger than the sum of its proper divisors (9734638432299).

21220111112121 is a wasteful number, since it uses less digits than its factorization.

21220111112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23344456776 (or 23344456773 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21220111112121 its reverse (12121111102212), we get a palindrome (33341222214333).

Subtracting from 21220111112121 its reverse (12121111102212), we obtain a palindrome (9099000009909).

The spelling of 21220111112121 in words is "twenty-one trillion, two hundred twenty billion, one hundred eleven million, one hundred twelve thousand, one hundred twenty-one".