11001221221 has 4 divisors (see below), whose sum is σ = 11001481452. Its totient is φ = 11000960992.

The previous prime is 11001221207. The next prime is 11001221233. The reversal of 11001221221 is 12212210011.

11001221221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12212210011 = 47639 ⋅256349.

It can be written as a sum of positive squares in 2 ways, for example, as 10430536900 + 570684321 = 102130^2 + 23889^2 .

It is a cyclic number.

It is not a de Polignac number, because 11001221221 - 2¹⁵ = 11001188453 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 (11001221201) 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, 50440 + ... + 156673.

It is an arithmetic number, because the mean of its divisors is an integer number (2750370363).

Almost surely, 2^11001221221 is an apocalyptic number.

It is an amenable number.

11001221221 is a deficient number, since it is larger than the sum of its proper divisors (260231).

11001221221 is an equidigital number, since it uses as much as digits as its factorization.

11001221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260230.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 11001221221 its reverse (12212210011), we get a palindrome (23213431232).

The spelling of 11001221221 in words is "eleven billion, one million, two hundred twenty-one thousand, two hundred twenty-one".