221202121 has 12 divisors (see below), whose sum is σ = 257559060. Its totient is φ = 189423360.

The previous prime is 221202119. The next prime is 221202131. The reversal of 221202121 is 121202122.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 169520400 + 51681721 = 13020^2 + 7189^2 .

It is not a de Polignac number, because 221202121 - 2¹ = 221202119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221202131) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 101281 + ... + 103441.

It is an arithmetic number, because the mean of its divisors is an integer number (21463255).

Almost surely, 2^221202121 is an apocalyptic number.

It is an amenable number.

221202121 is a deficient number, since it is larger than the sum of its proper divisors (36356939).

221202121 is a wasteful number, since it uses less digits than its factorization.

221202121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4264 (or 4257 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 221202121 is about 14872.8652585842. The cubic root of 221202121 is about 604.7786190001.

Adding to 221202121 its reverse (121202122), we get a palindrome (342404243).

Subtracting from 221202121 its reverse (121202122), we obtain a palindrome (99999999).

The spelling of 221202121 in words is "two hundred twenty-one million, two hundred two thousand, one hundred twenty-one".