11111111221121 has 8 divisors (see below), whose sum is σ = 11766257593344. Its totient is φ = 10456137248320.

The previous prime is 11111111221057. The next prime is 11111111221139. The reversal of 11111111221121 is 12112211111111.

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 11111111221121 - 2⁶ = 11111111221057 is a prime.

It is a super-3 number, since 3×11111111221121³ (a number of 40 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11111111221121.

It is not an unprimeable number, because it can be changed into a prime (11111111226121) 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, 42967145 + ... + 43224966.

It is an arithmetic number, because the mean of its divisors is an integer number (1470782199168).

Almost surely, 2^{11111111221121} is an apocalyptic number.

It is an amenable number.

11111111221121 is a deficient number, since it is larger than the sum of its proper divisors (655146372223).

11111111221121 is an equidigital number, since it uses as much as digits as its factorization.

11111111221121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86199711.

The product of its digits is 8, while the sum is 17.

Adding to 11111111221121 its reverse (12112211111111), we get a palindrome (23223322332232).

The spelling of 11111111221121 in words is "eleven trillion, one hundred eleven billion, one hundred eleven million, two hundred twenty-one thousand, one hundred twenty-one".