221421124121 has 4 divisors (see below), whose sum is σ = 224088848592. Its totient is φ = 218753399652.

The previous prime is 221421124103. The next prime is 221421124147. The reversal of 221421124121 is 121421124122.

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 a de Polignac number, because none of the positive numbers 2^k-221421124121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221421124181) 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, 1333862111 + ... + 1333862276.

It is an arithmetic number, because the mean of its divisors is an integer number (56022212148).

Almost surely, 2^221421124121 is an apocalyptic number.

It is an amenable number.

221421124121 is a deficient number, since it is larger than the sum of its proper divisors (2667724471).

221421124121 is an equidigital number, since it uses as much as digits as its factorization.

221421124121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2667724470.

The product of its digits is 512, while the sum is 23.

Adding to 221421124121 its reverse (121421124122), we get a palindrome (342842248243).

Subtracting from 221421124121 its reverse (121421124122), we obtain a palindrome (99999999999).

The spelling of 221421124121 in words is "two hundred twenty-one billion, four hundred twenty-one million, one hundred twenty-four thousand, one hundred twenty-one".