21201111220111 has 2 divisors, whose sum is σ = 21201111220112. Its totient is φ = 21201111220110.

The previous prime is 21201111220109. The next prime is 21201111220127. The reversal of 21201111220111 is 11102211110212.

It is an a-pointer prime, because the next prime (21201111220127) can be obtained adding 21201111220111 to its sum of digits (16).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21201111220111 - 2¹ = 21201111220109 is a prime.

Together with 21201111220109, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201111220171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600555610055 + 10600555610056.

It is an arithmetic number, because the mean of its divisors is an integer number (10600555610056).

Almost surely, 2^{21201111220111} is an apocalyptic number.

21201111220111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201111220111 is an equidigital number, since it uses as much as digits as its factorization.

21201111220111 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21201111220111 its reverse (11102211110212), we get a palindrome (32303322330323).

The spelling of 21201111220111 in words is "twenty-one trillion, two hundred one billion, one hundred eleven million, two hundred twenty thousand, one hundred eleven".