11131221 has 4 divisors (see below), whose sum is σ = 14841632. Its totient is φ = 7420812.

The previous prime is 11131187. The next prime is 11131229. The reversal of 11131221 is 12213111.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12213111 = 3 ⋅4071037.

It is not a de Polignac number, because 11131221 - 2¹⁵ = 11098453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11131197 and 11131206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11131229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1855201 + ... + 1855206.

It is an arithmetic number, because the mean of its divisors is an integer number (3710408).

Almost surely, 2^11131221 is an apocalyptic number.

It is an amenable number.

11131221 is a deficient number, since it is larger than the sum of its proper divisors (3710411).

11131221 is an equidigital number, since it uses as much as digits as its factorization.

11131221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3710410.

The product of its digits is 12, while the sum is 12.

The square root of 11131221 is about 3336.3484530247. The cubic root of 11131221 is about 223.2788577809.

Adding to 11131221 its reverse (12213111), we get a palindrome (23344332).

The spelling of 11131221 in words is "eleven million, one hundred thirty-one thousand, two hundred twenty-one".