11121221111 has 16 divisors (see below), whose sum is σ = 14931990528. Its totient is φ = 7999279200.

The previous prime is 11121221101. The next prime is 11121221131. The reversal of 11121221111 is 11112212111.

It is not a de Polignac number, because 11121221111 - 2¹⁴ = 11121204727 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11121221101) 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, 5554055 + ... + 5556056.

It is an arithmetic number, because the mean of its divisors is an integer number (933249408).

Almost surely, 2^11121221111 is an apocalyptic number.

11121221111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

11121221111 is a deficient number, since it is larger than the sum of its proper divisors (3810769417).

11121221111 is a wasteful number, since it uses less digits than its factorization.

11121221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11110142.

The product of its digits is 8, while the sum is 14.

Adding to 11121221111 its reverse (11112212111), we get a palindrome (22233433222).

It can be divided in two parts, 11121 and 221111, that added together give a palindrome (232232).

The spelling of 11121221111 in words is "eleven billion, one hundred twenty-one million, two hundred twenty-one thousand, one hundred eleven".