21112021121 has 4 divisors (see below), whose sum is σ = 21112344000. Its totient is φ = 21111698244.

The previous prime is 21112021111. The next prime is 21112021157. The reversal of 21112021121 is 12112021112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21112021121 - 2¹⁴ = 21112004737 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112021096 and 21112021105.

It is not an unprimeable number, because it can be changed into a prime (21112021111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24821 + ... + 206978.

It is an arithmetic number, because the mean of its divisors is an integer number (5278086000).

Almost surely, 2^21112021121 is an apocalyptic number.

It is an amenable number.

21112021121 is a deficient number, since it is larger than the sum of its proper divisors (322879).

21112021121 is an equidigital number, since it uses as much as digits as its factorization.

21112021121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322878.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21112021121 its reverse (12112021112), we get a palindrome (33224042233).

Subtracting from 21112021121 its reverse (12112021112), we obtain a palindrome (9000000009).

The spelling of 21112021121 in words is "twenty-one billion, one hundred twelve million, twenty-one thousand, one hundred twenty-one".