21111123211 has 8 divisors (see below), whose sum is σ = 21151110384. Its totient is φ = 21071163360.

The previous prime is 21111123203. The next prime is 21111123227. The reversal of 21111123211 is 11232111112.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21111123211 - 2³ = 21111123203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111123251) 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, 2148636 + ... + 2158438.

It is an arithmetic number, because the mean of its divisors is an integer number (2643888798).

Almost surely, 2^21111123211 is an apocalyptic number.

21111123211 is a deficient number, since it is larger than the sum of its proper divisors (39987173).

21111123211 is an equidigital number, since it uses as much as digits as its factorization.

21111123211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13661.

The product of its digits is 24, while the sum is 16.

Adding to 21111123211 its reverse (11232111112), we get a palindrome (32343234323).

The spelling of 21111123211 in words is "twenty-one billion, one hundred eleven million, one hundred twenty-three thousand, two hundred eleven".