221121121211221 has 16 divisors (see below), whose sum is σ = 290193132418560. Its totient is φ = 163233636983280.

The previous prime is 221121121211203. The next prime is 221121121211273. The reversal of 221121121211221 is 122112121121122.

It is a cyclic number.

It is not a de Polignac number, because 221121121211221 - 2¹⁵ = 221121121178453 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221121121211192 and 221121121211201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221121121211021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75571126771 + ... + 75571129696.

It is an arithmetic number, because the mean of its divisors is an integer number (18137070776160).

Almost surely, 2^{221121121211221} is an apocalyptic number.

It is an amenable number.

221121121211221 is a deficient number, since it is larger than the sum of its proper divisors (69072011207339).

221121121211221 is a wasteful number, since it uses less digits than its factorization.

221121121211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151142256504.

The product of its digits is 128, while the sum is 22.

Adding to 221121121211221 its reverse (122112121121122), we get a palindrome (343233242332343).

Subtracting from 221121121211221 its reverse (122112121121122), we obtain a palindrome (99009000090099).

It can be divided in two parts, 2211211 and 21211221, that added together give a palindrome (23422432).

The spelling of 221121121211221 in words is "two hundred twenty-one trillion, one hundred twenty-one billion, one hundred twenty-one million, two hundred eleven thousand, two hundred twenty-one".