11231131221 has 24 divisors (see below), whose sum is σ = 16830253440. Its totient is φ = 7484454432.

The previous prime is 11231131207. The next prime is 11231131231. The reversal of 11231131221 is 12213113211.

It is not a de Polignac number, because 11231131221 - 2⁶ = 11231131157 is a prime.

It is a super-3 number, since 3×11231131221³ (a number of 31 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 11231131194 and 11231131203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11231131231) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 726945 + ... + 742233.

It is an arithmetic number, because the mean of its divisors is an integer number (701260560).

Almost surely, 2^11231131221 is an apocalyptic number.

It is an amenable number.

11231131221 is a deficient number, since it is larger than the sum of its proper divisors (5599122219).

11231131221 is an equidigital number, since it uses as much as digits as its factorization.

11231131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18327 (or 18315 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

Adding to 11231131221 its reverse (12213113211), we get a palindrome (23444244432).

The spelling of 11231131221 in words is "eleven billion, two hundred thirty-one million, one hundred thirty-one thousand, two hundred twenty-one".