11111221112221 has 16 divisors (see below), whose sum is σ = 11857187865600. Its totient is φ = 10394287804800.

The previous prime is 11111221112129. The next prime is 11111221112267. The reversal of 11111221112221 is 12221112211111.

It is a cyclic number.

It is not a de Polignac number, because 11111221112221 - 2¹⁹ = 11111220587933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111221119221) 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, 39962881 + ... + 40239958.

It is an arithmetic number, because the mean of its divisors is an integer number (741074241600).

Almost surely, 2^{11111221112221} is an apocalyptic number.

It is an amenable number.

11111221112221 is a deficient number, since it is larger than the sum of its proper divisors (745966753379).

11111221112221 is a wasteful number, since it uses less digits than its factorization.

11111221112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80203020.

The product of its digits is 32, while the sum is 19.

Adding to 11111221112221 its reverse (12221112211111), we get a palindrome (23332333323332).

The spelling of 11111221112221 in words is "eleven trillion, one hundred eleven billion, two hundred twenty-one million, one hundred twelve thousand, two hundred twenty-one".