221202211221 has 24 divisors (see below), whose sum is σ = 324012016536. Its totient is φ = 145393781760.

The previous prime is 221202211211. The next prime is 221202211249. The reversal of 221202211221 is 122112202122.

It is a happy number.

221202211221 is a `hidden beast` number, since 221 + 2 + 0 + 221 + 1 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 52207223121 + 168994988100 = 228489^2 + 411090^2 .

It is not a de Polignac number, because 221202211221 - 2⁷ = 221202211093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221202211194 and 221202211203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221202211211) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1739421 + ... + 1862253.

It is an arithmetic number, because the mean of its divisors is an integer number (13500500689).

Almost surely, 2^221202211221 is an apocalyptic number.

It is an amenable number.

221202211221 is a deficient number, since it is larger than the sum of its proper divisors (102809805315).

221202211221 is a wasteful number, since it uses less digits than its factorization.

221202211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125653 (or 125650 counting only the distinct ones).

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

Adding to 221202211221 its reverse (122112202122), we get a palindrome (343314413343).

Subtracting from 221202211221 its reverse (122112202122), we obtain a palindrome (99090009099).

The spelling of 221202211221 in words is "two hundred twenty-one billion, two hundred two million, two hundred eleven thousand, two hundred twenty-one".