21122222111 has 2 divisors, whose sum is σ = 21122222112. Its totient is φ = 21122222110.

The previous prime is 21122222083. The next prime is 21122222131. The reversal of 21122222111 is 11122222112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21122222111 is a prime.

It is a super-2 number, since 2×21122222111² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21122222111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21122222131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561111055 + 10561111056.

It is an arithmetic number, because the mean of its divisors is an integer number (10561111056).

Almost surely, 2^21122222111 is an apocalyptic number.

21122222111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122222111 is an equidigital number, since it uses as much as digits as its factorization.

21122222111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64, while the sum is 17.

Adding to 21122222111 its reverse (11122222112), we get a palindrome (32244444223).

Subtracting from 21122222111 its reverse (11122222112), we obtain a palindrome (9999999999).

The spelling of 21122222111 in words is "twenty-one billion, one hundred twenty-two million, two hundred twenty-two thousand, one hundred eleven".