21112211220121 has 16 divisors (see below), whose sum is σ = 24320533221376. Its totient is φ = 17951989196736.

The previous prime is 21112211220119. The next prime is 21112211220187. The reversal of 21112211220121 is 12102211221112.

It is a happy number.

It is not a de Polignac number, because 21112211220121 - 2¹ = 21112211220119 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21112211224121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8300215 + ... + 10541251.

It is an arithmetic number, because the mean of its divisors is an integer number (1520033326336).

Almost surely, 2^{21112211220121} is an apocalyptic number.

It is an amenable number.

21112211220121 is a deficient number, since it is larger than the sum of its proper divisors (3208322001255).

21112211220121 is a wasteful number, since it uses less digits than its factorization.

21112211220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2251768.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21112211220121 its reverse (12102211221112), we get a palindrome (33214422441233).

Subtracting from 21112211220121 its reverse (12102211221112), we obtain a palindrome (9009999999009).

The spelling of 21112211220121 in words is "twenty-one trillion, one hundred twelve billion, two hundred eleven million, two hundred twenty thousand, one hundred twenty-one".