221121220121 has 4 divisors (see below), whose sum is σ = 221144896512. Its totient is φ = 221097543732.

The previous prime is 221121220109. The next prime is 221121220147. The reversal of 221121220121 is 121022121122.

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-221121220121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221121220121.

It is not an unprimeable number, because it can be changed into a prime (221121228121) 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, 11824181 + ... + 11842866.

It is an arithmetic number, because the mean of its divisors is an integer number (55286224128).

Almost surely, 2^221121220121 is an apocalyptic number.

It is an amenable number.

221121220121 is a deficient number, since it is larger than the sum of its proper divisors (23676391).

221121220121 is an equidigital number, since it uses as much as digits as its factorization.

221121220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23676390.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 221121220121 its reverse (121022121122), we get a palindrome (342143341243).

The spelling of 221121220121 in words is "two hundred twenty-one billion, one hundred twenty-one million, two hundred twenty thousand, one hundred twenty-one".