21101221011121 has 4 divisors (see below), whose sum is σ = 21140225117044. Its totient is φ = 21062216905200.

The previous prime is 21101221011119. The next prime is 21101221011133. The reversal of 21101221011121 is 12111012210112.

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 5703327290896 + 15397893720225 = 2388164^2 + 3924015^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101221011121 - 2¹ = 21101221011119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101221011095 and 21101221011104.

It is not an unprimeable number, because it can be changed into a prime (21101221018121) 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 3 ways as a sum of consecutive naturals, for example, 19502052150 + ... + 19502053231.

It is an arithmetic number, because the mean of its divisors is an integer number (5285056279261).

Almost surely, 2^{21101221011121} is an apocalyptic number.

It is an amenable number.

21101221011121 is a deficient number, since it is larger than the sum of its proper divisors (39004105923).

21101221011121 is an equidigital number, since it uses as much as digits as its factorization.

21101221011121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39004105922.

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

Adding to 21101221011121 its reverse (12111012210112), we get a palindrome (33212233221233).

The spelling of 21101221011121 in words is "twenty-one trillion, one hundred one billion, two hundred twenty-one million, eleven thousand, one hundred twenty-one".