2121110111221 has 8 divisors (see below), whose sum is σ = 2245984628760. Its totient is φ = 1996247075328.

The previous prime is 2121110111201. The next prime is 2121110111243. The reversal of 2121110111221 is 1221110111212.

It can be written as a sum of positive squares in 4 ways, for example, as 1479845487121 + 641264624100 = 1216489^2 + 800790^2 .

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 2121110111221 - 2⁹ = 2121110110709 is a prime.

It is a super-2 number, since 2×2121110111221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121110111195 and 2121110111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121110111201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2488606 + ... + 3230383.

It is an arithmetic number, because the mean of its divisors is an integer number (280748078595).

Almost surely, 2^{2121110111221} is an apocalyptic number.

It is an amenable number.

2121110111221 is a deficient number, since it is larger than the sum of its proper divisors (124874517539).

2121110111221 is a wasteful number, since it uses less digits than its factorization.

2121110111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5740823.

The product of its (nonzero) digits is 16, while the sum is 16.

Adding to 2121110111221 its reverse (1221110111212), we get a palindrome (3342220222433).

Subtracting from 2121110111221 its reverse (1221110111212), we obtain a palindrome (900000000009).

The spelling of 2121110111221 in words is "two trillion, one hundred twenty-one billion, one hundred ten million, one hundred eleven thousand, two hundred twenty-one".