11123231221 has 4 divisors (see below), whose sum is σ = 11124765792. Its totient is φ = 11121696652.

The previous prime is 11123231219. The next prime is 11123231267. The reversal of 11123231221 is 12213232111.

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: 12213232111 = 223 ⋅54767857.

It is a cyclic number.

It is not a de Polignac number, because 11123231221 - 2¹ = 11123231219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11123231281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 756361 + ... + 770926.

It is an arithmetic number, because the mean of its divisors is an integer number (2781191448).

Almost surely, 2^11123231221 is an apocalyptic number.

It is an amenable number.

11123231221 is a deficient number, since it is larger than the sum of its proper divisors (1534571).

11123231221 is an equidigital number, since it uses as much as digits as its factorization.

11123231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1534570.

The product of its digits is 144, while the sum is 19.

Adding to 11123231221 its reverse (12213232111), we get a palindrome (23336463332).

The spelling of 11123231221 in words is "eleven billion, one hundred twenty-three million, two hundred thirty-one thousand, two hundred twenty-one".