21201121112111 has 2 divisors, whose sum is σ = 21201121112112. Its totient is φ = 21201121112110.

The previous prime is 21201121112099. The next prime is 21201121112161. The reversal of 21201121112111 is 11121112110212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21201121112111 - 2¹⁰ = 21201121111087 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21201121112111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201121112161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600560556055 + 10600560556056.

It is an arithmetic number, because the mean of its divisors is an integer number (10600560556056).

Almost surely, 2^{21201121112111} is an apocalyptic number.

21201121112111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201121112111 is an equidigital number, since it uses as much as digits as its factorization.

21201121112111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 21201121112111 its reverse (11121112110212), we get a palindrome (32322233222323).

The spelling of 21201121112111 in words is "twenty-one trillion, two hundred one billion, one hundred twenty-one million, one hundred twelve thousand, one hundred eleven".