11111111221231 has 16 divisors (see below), whose sum is σ = 12823190639424. Its totient is φ = 9430389448704.

The previous prime is 11111111221187. The next prime is 11111111221247. The reversal of 11111111221231 is 13212211111111.

It is a happy number.

It is not a de Polignac number, because 11111111221231 - 2⁹ = 11111111220719 is a prime.

It is a super-2 number, since 2×11111111221231² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11111111221199 and 11111111221208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111111221261) 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, 5981986 + ... + 7616191.

It is an arithmetic number, because the mean of its divisors is an integer number (801449414964).

Almost surely, 2^{11111111221231} is an apocalyptic number.

11111111221231 is a deficient number, since it is larger than the sum of its proper divisors (1712079418193).

11111111221231 is a wasteful number, since it uses less digits than its factorization.

11111111221231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13599330.

The product of its digits is 24, while the sum is 19.

Adding to 11111111221231 its reverse (13212211111111), we get a palindrome (24323322332342).

The spelling of 11111111221231 in words is "eleven trillion, one hundred eleven billion, one hundred eleven million, two hundred twenty-one thousand, two hundred thirty-one".