221221201221 has 10 divisors (see below), whose sum is σ = 330466238982. Its totient is φ = 147480800760.

The previous prime is 221221201219. The next prime is 221221201241. The reversal of 221221201221 is 122102122122.

It is a happy number.

221221201221 is a `hidden beast` number, since 2 + 21 + 221 + 201 + 221 = 666.

221221201221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 213208445025 + 8012756196 = 461745^2 + 89514^2 .

It is not a de Polignac number, because 221221201221 - 2¹ = 221221201219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221221201194 and 221221201203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221201241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1365562890 + ... + 1365563051.

Almost surely, 2^221221201221 is an apocalyptic number.

It is an amenable number.

221221201221 is a deficient number, since it is larger than the sum of its proper divisors (109245037761).

221221201221 is an equidigital number, since it uses as much as digits as its factorization.

221221201221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2731125953 (or 2731125944 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 221221201221 its reverse (122102122122), we get a palindrome (343323323343).

The spelling of 221221201221 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred one thousand, two hundred twenty-one".