11221220221 has 4 divisors (see below), whose sum is σ = 11221432092. Its totient is φ = 11221008352.

The previous prime is 11221220201. The next prime is 11221220321. The reversal of 11221220221 is 12202212211.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4978008025 + 6243212196 = 70555^2 + 79014^2 .

It is a cyclic number.

It is not a de Polignac number, because 11221220221 - 2¹³ = 11221212029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11221220195 and 11221220204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11221220201) 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, 51465 + ... + 158401.

It is an arithmetic number, because the mean of its divisors is an integer number (2805358023).

Almost surely, 2^11221220221 is an apocalyptic number.

It is an amenable number.

11221220221 is a deficient number, since it is larger than the sum of its proper divisors (211871).

11221220221 is a wasteful number, since it uses less digits than its factorization.

11221220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211870.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 11221220221 its reverse (12202212211), we get a palindrome (23423432432).

The spelling of 11221220221 in words is "eleven billion, two hundred twenty-one million, two hundred twenty thousand, two hundred twenty-one".