21221111012111 has 2 divisors, whose sum is σ = 21221111012112. Its totient is φ = 21221111012110.

The previous prime is 21221111012093. The next prime is 21221111012119. The reversal of 21221111012111 is 11121011112212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221111012111 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21221111012111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221111012119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610555506055 + 10610555506056.

It is an arithmetic number, because the mean of its divisors is an integer number (10610555506056).

Almost surely, 2^{21221111012111} is an apocalyptic number.

21221111012111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221111012111 is an equidigital number, since it uses as much as digits as its factorization.

21221111012111 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 17.

Adding to 21221111012111 its reverse (11121011112212), we get a palindrome (32342122124323).

The spelling of 21221111012111 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, twelve thousand, one hundred eleven".