11231221 has 4 divisors (see below), whose sum is σ = 11238112. Its totient is φ = 11224332.

The previous prime is 11231219. The next prime is 11231243. The reversal of 11231221 is 12213211.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12213211 = 167 ⋅73133.

It is a cyclic number.

It is not a de Polignac number, because 11231221 - 2¹ = 11231219 is a prime.

It is a super-2 number, since 2×11231221² = 252280650301682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11231201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 526 + ... + 4768.

It is an arithmetic number, because the mean of its divisors is an integer number (2809528).

Almost surely, 2^11231221 is an apocalyptic number.

It is an amenable number.

11231221 is a deficient number, since it is larger than the sum of its proper divisors (6891).

11231221 is an equidigital number, since it uses as much as digits as its factorization.

11231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6890.

The product of its digits is 24, while the sum is 13.

The square root of 11231221 is about 3351.3013890129. The cubic root of 11231221 is about 223.9454918923.

Adding to 11231221 its reverse (12213211), we get a palindrome (23444432).

The spelling of 11231221 in words is "eleven million, two hundred thirty-one thousand, two hundred twenty-one".