221242404242121 has 4 divisors (see below), whose sum is σ = 294989872322832. Its totient is φ = 147494936161412.

The previous prime is 221242404242117. The next prime is 221242404242141. The reversal of 221242404242121 is 121242404242122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221242404242121 - 2² = 221242404242117 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221242404242141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36873734040351 + ... + 36873734040356.

It is an arithmetic number, because the mean of its divisors is an integer number (73747468080708).

Almost surely, 2^{221242404242121} is an apocalyptic number.

It is an amenable number.

221242404242121 is a deficient number, since it is larger than the sum of its proper divisors (73747468080711).

221242404242121 is an equidigital number, since it uses as much as digits as its factorization.

221242404242121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73747468080710.

The product of its (nonzero) digits is 32768, while the sum is 33.

Adding to 221242404242121 its reverse (121242404242122), we get a palindrome (342484808484243).

Subtracting from 221242404242121 its reverse (121242404242122), we obtain a palindrome (99999999999999).

The spelling of 221242404242121 in words is "two hundred twenty-one trillion, two hundred forty-two billion, four hundred four million, two hundred forty-two thousand, one hundred twenty-one".