221221222121221 has 8 divisors (see below), whose sum is σ = 252850102438784. Its totient is φ = 189598803950160.

The previous prime is 221221222121219. The next prime is 221221222121239. The reversal of 221221222121221 is 122121222122122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221221222121221 - 2¹ = 221221222121219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221222121521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1615463265 + ... + 1615600198.

It is an arithmetic number, because the mean of its divisors is an integer number (31606262804848).

Almost surely, 2^{221221222121221} is an apocalyptic number.

It is an amenable number.

221221222121221 is a deficient number, since it is larger than the sum of its proper divisors (31628880317563).

221221222121221 is an equidigital number, since it uses as much as digits as its factorization.

221221222121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3231073251.

The product of its digits is 1024, while the sum is 25.

Adding to 221221222121221 its reverse (122121222122122), we get a palindrome (343342444243343).

Subtracting from 221221222121221 its reverse (122121222122122), we obtain a palindrome (99099999999099).

The spelling of 221221222121221 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, two hundred twenty-two million, one hundred twenty-one thousand, two hundred twenty-one".