211111111111 has 4 divisors (see below), whose sum is σ = 211133224224. Its totient is φ = 211088998000.

The previous prime is 211111111091. The next prime is 211111111157. The reversal of 211111111111 is 111111111112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 211111111111 - 2²³ = 211102722503 is a prime.

It is a Duffinian number.

211111111111 is a modest number, since divided by 1111111 gives 21111 as remainder.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 211111111091 and 211111111100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211111111171) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11042230 + ... + 11061331.

It is an arithmetic number, because the mean of its divisors is an integer number (52783306056).

Almost surely, 2^211111111111 is an apocalyptic number.

211111111111 is a deficient number, since it is larger than the sum of its proper divisors (22113113).

211111111111 is an equidigital number, since it uses as much as digits as its factorization.

211111111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22113112.

The product of its digits is 2, while the sum is 13.

Adding to 211111111111 its reverse (111111111112), we get a palindrome (322222222223).

Subtracting from 211111111111 its reverse (111111111112), we obtain a palindrome (99999999999).

It can be divided in two parts, 21111111111 and 1, that added together give a palindrome (21111111112).

The spelling of 211111111111 in words is "two hundred eleven billion, one hundred eleven million, one hundred eleven thousand, one hundred eleven".