221212210221 has 20 divisors (see below), whose sum is σ = 341847735900. Its totient is φ = 142389467136.

The previous prime is 221212210213. The next prime is 221212210259. The reversal of 221212210221 is 122012212122.

It is a happy number.

221212210221 is a `hidden beast` number, since 2 + 21 + 212 + 210 + 221 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 71791307721 + 149420902500 = 267939^2 + 386550^2 .

It is not a de Polignac number, because 221212210221 - 2³ = 221212210213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221212210194 and 221212210203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212210291) 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 19 ways as a sum of consecutive naturals, for example, 47084116 + ... + 47088813.

It is an arithmetic number, because the mean of its divisors is an integer number (17092386795).

Almost surely, 2^221212210221 is an apocalyptic number.

It is an amenable number.

221212210221 is a deficient number, since it is larger than the sum of its proper divisors (120635525679).

221212210221 is an equidigital number, since it uses as much as digits as its factorization.

221212210221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94172970 (or 94172961 counting only the distinct ones).

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

Adding to 221212210221 its reverse (122012212122), we get a palindrome (343224422343).

The spelling of 221212210221 in words is "two hundred twenty-one billion, two hundred twelve million, two hundred ten thousand, two hundred twenty-one".