21121112111121 has 64 divisors (see below), whose sum is σ = 35780897940480. Its totient is φ = 12198032784000.

The previous prime is 21121112111119. The next prime is 21121112111173. The reversal of 21121112111121 is 12111121112112.

21121112111121 is a `hidden beast` number, since 211 + 211 + 1 + 211 + 11 + 21 = 666.

It is not a de Polignac number, because 21121112111121 - 2¹ = 21121112111119 is a prime.

It is a super-2 number, since 2×21121112111121² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121112111094 and 21121112111103.

It is not an unprimeable number, because it can be changed into a prime (21121112111191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 19645095 + ... + 20692316.

It is an arithmetic number, because the mean of its divisors is an integer number (559076530320).

Almost surely, 2^{21121112111121} is an apocalyptic number.

It is an amenable number.

21121112111121 is a deficient number, since it is larger than the sum of its proper divisors (14659785829359).

21121112111121 is a wasteful number, since it uses less digits than its factorization.

21121112111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40337515 (or 40337509 counting only the distinct ones).

The product of its digits is 16, while the sum is 18.

Adding to 21121112111121 its reverse (12111121112112), we get a palindrome (33232233223233).

Subtracting from 21121112111121 its reverse (12111121112112), we obtain a palindrome (9009990999009).

The spelling of 21121112111121 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred twelve million, one hundred eleven thousand, one hundred twenty-one".