11111212111 has 4 divisors (see below), whose sum is σ = 11299537800. Its totient is φ = 10922886424.

The previous prime is 11111212109. The next prime is 11111212153. The reversal of 11111212111 is 11121211111.

11111212111 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 11111212111 - 2¹ = 11111212109 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11111212091 and 11111212100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111212811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94162756 + ... + 94162873.

It is an arithmetic number, because the mean of its divisors is an integer number (2824884450).

Almost surely, 2^11111212111 is an apocalyptic number.

11111212111 is a deficient number, since it is larger than the sum of its proper divisors (188325689).

11111212111 is an equidigital number, since it uses as much as digits as its factorization.

11111212111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188325688.

The product of its digits is 4, while the sum is 13.

Adding to 11111212111 its reverse (11121211111), we get a palindrome (22232423222).

It can be divided in two parts, 11 and 111212111, that multiplied together give a palindrome (1223333221).

The spelling of 11111212111 in words is "eleven billion, one hundred eleven million, two hundred twelve thousand, one hundred eleven".