11131131221 has 32 divisors (see below), whose sum is σ = 13592130048. Its totient is φ = 8909936640.

The previous prime is 11131131181. The next prime is 11131131223. The reversal of 11131131221 is 12213113111.

It is a cyclic number.

It is not a de Polignac number, because 11131131221 - 2¹⁸ = 11130869077 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 11131131221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11131131223) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1341341 + ... + 1349613.

It is an arithmetic number, because the mean of its divisors is an integer number (424754064).

Almost surely, 2^11131131221 is an apocalyptic number.

It is an amenable number.

11131131221 is a deficient number, since it is larger than the sum of its proper divisors (2460998827).

11131131221 is a wasteful number, since it uses less digits than its factorization.

11131131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8501.

The product of its digits is 36, while the sum is 17.

Adding to 11131131221 its reverse (12213113111), we get a palindrome (23344244332).

The spelling of 11131131221 in words is "eleven billion, one hundred thirty-one million, one hundred thirty-one thousand, two hundred twenty-one".