21201122101111 has 4 divisors (see below), whose sum is σ = 21411034201224. Its totient is φ = 20991210001000.

The previous prime is 21201122101067. The next prime is 21201122101157. The reversal of 21201122101111 is 11110122110212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21201122101111 - 2¹⁹ = 21201121576823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201122101811) 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, 104956049905 + ... + 104956050106.

It is an arithmetic number, because the mean of its divisors is an integer number (5352758550306).

Almost surely, 2^{21201122101111} is an apocalyptic number.

21201122101111 is a deficient number, since it is larger than the sum of its proper divisors (209912100113).

21201122101111 is a wasteful number, since it uses less digits than its factorization.

21201122101111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209912100112.

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

Adding to 21201122101111 its reverse (11110122110212), we get a palindrome (32311244211323).

The spelling of 21201122101111 in words is "twenty-one trillion, two hundred one billion, one hundred twenty-two million, one hundred one thousand, one hundred eleven".