21112222111 has 16 divisors (see below), whose sum is σ = 22169540160. Its totient is φ = 20077424640.

The previous prime is 21112222081. The next prime is 21112222121. The reversal of 21112222111 is 11122221112.

It is a cyclic number.

It is not a de Polignac number, because 21112222111 - 2¹⁹ = 21111697823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112222121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2369581 + ... + 2378473.

It is an arithmetic number, because the mean of its divisors is an integer number (1385596260).

Almost surely, 2^21112222111 is an apocalyptic number.

21112222111 is a deficient number, since it is larger than the sum of its proper divisors (1057318049).

21112222111 is a wasteful number, since it uses less digits than its factorization.

21112222111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10146.

The product of its digits is 32, while the sum is 16.

Adding to 21112222111 its reverse (11122221112), we get a palindrome (32234443223).

Subtracting from 21112222111 its reverse (11122221112), we obtain a palindrome (9990000999).

It can be divided in two parts, 2111 and 2222111, that added together give a palindrome (2224222).

The spelling of 21112222111 in words is "twenty-one billion, one hundred twelve million, two hundred twenty-two thousand, one hundred eleven".