221221120221 has 40 divisors (see below), whose sum is σ = 334073897784. Its totient is φ = 145873612800.

The previous prime is 221221120217. The next prime is 221221120229. The reversal of 221221120221 is 122021122122.

It is a happy number.

221221120221 is a `hidden beast` number, since 2 + 212 + 211 + 20 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 202864664025 + 18356456196 = 450405^2 + 135486^2 .

It is not a de Polignac number, because 221221120221 - 2² = 221221120217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221221120194 and 221221120203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221120229) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 8437885 + ... + 8464061.

Almost surely, 2^221221120221 is an apocalyptic number.

It is an amenable number.

221221120221 is a deficient number, since it is larger than the sum of its proper divisors (112852777563).

221221120221 is a wasteful number, since it uses less digits than its factorization.

221221120221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27323 (or 27314 counting only the distinct ones).

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

Adding to 221221120221 its reverse (122021122122), we get a palindrome (343242242343).

The spelling of 221221120221 in words is "two hundred twenty-one billion, two hundred twenty-one million, one hundred twenty thousand, two hundred twenty-one".