21110111001121 has 4 divisors (see below), whose sum is σ = 21456178394644. Its totient is φ = 20764043607600.

The previous prime is 21110111001107. The next prime is 21110111001151. The reversal of 21110111001121 is 12110011101112.

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 9612721992721 + 11497389008400 = 3100439^2 + 3390780^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110111001121 - 2²⁹ = 21109574130209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21110111001151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 173033696670 + ... + 173033696791.

It is an arithmetic number, because the mean of its divisors is an integer number (5364044598661).

Almost surely, 2^{21110111001121} is an apocalyptic number.

It is an amenable number.

21110111001121 is a deficient number, since it is larger than the sum of its proper divisors (346067393523).

21110111001121 is an equidigital number, since it uses as much as digits as its factorization.

21110111001121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346067393522.

The product of its (nonzero) digits is 4, while the sum is 13.

Adding to 21110111001121 its reverse (12110011101112), we get a palindrome (33220122102233).

Subtracting from 21110111001121 its reverse (12110011101112), we obtain a palindrome (9000099900009).

The spelling of 21110111001121 in words is "twenty-one trillion, one hundred ten billion, one hundred eleven million, one thousand, one hundred twenty-one".