11122221221 has 4 divisors (see below), whose sum is σ = 11122920972. Its totient is φ = 11121521472.

The previous prime is 11122221211. The next prime is 11122221247. The reversal of 11122221221 is 12212222111.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8751602500 + 2370618721 = 93550^2 + 48689^2 .

It is a cyclic number.

It is not a de Polignac number, because 11122221221 - 2¹⁸ = 11121959077 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11122221221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11122221211) 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, 325466 + ... + 358011.

It is an arithmetic number, because the mean of its divisors is an integer number (2780730243).

Almost surely, 2^11122221221 is an apocalyptic number.

It is an amenable number.

11122221221 is a deficient number, since it is larger than the sum of its proper divisors (699751).

11122221221 is an equidigital number, since it uses as much as digits as its factorization.

11122221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 699750.

The product of its digits is 64, while the sum is 17.

Adding to 11122221221 its reverse (12212222111), we get a palindrome (23334443332).

The spelling of 11122221221 in words is "eleven billion, one hundred twenty-two million, two hundred twenty-one thousand, two hundred twenty-one".