21220111220111 has 2 divisors, whose sum is σ = 21220111220112. Its totient is φ = 21220111220110.

The previous prime is 21220111220083. The next prime is 21220111220137. The reversal of 21220111220111 is 11102211102212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21220111220111 - 2⁴² = 16822064709007 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21220111220111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21220111220141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610055610055 + 10610055610056.

It is an arithmetic number, because the mean of its divisors is an integer number (10610055610056).

Almost surely, 2^{21220111220111} is an apocalyptic number.

21220111220111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220111220111 is an equidigital number, since it uses as much as digits as its factorization.

21220111220111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21220111220111 its reverse (11102211102212), we get a palindrome (32322322322323).

The spelling of 21220111220111 in words is "twenty-one trillion, two hundred twenty billion, one hundred eleven million, two hundred twenty thousand, one hundred eleven".