21112122111 has 8 divisors (see below), whose sum is σ = 28488647040. Its totient is φ = 13905172632.

The previous prime is 21112122091. The next prime is 21112122127. The reversal of 21112122111 is 11122121112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21112122111 - 2⁵ = 21112122079 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112122151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42393571 + ... + 42394068.

It is an arithmetic number, because the mean of its divisors is an integer number (3561080880).

Almost surely, 2^21112122111 is an apocalyptic number.

21112122111 is a deficient number, since it is larger than the sum of its proper divisors (7376524929).

21112122111 is an equidigital number, since it uses as much as digits as its factorization.

21112122111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84787725.

The product of its digits is 16, while the sum is 15.

Adding to 21112122111 its reverse (11122121112), we get a palindrome (32234243223).

Subtracting from 21112122111 its reverse (11122121112), we obtain a palindrome (9990000999).

The spelling of 21112122111 in words is "twenty-one billion, one hundred twelve million, one hundred twenty-two thousand, one hundred eleven".