2121111221 has 8 divisors (see below), whose sum is σ = 2220028224. Its totient is φ = 2022752160.

The previous prime is 2121111217. The next prime is 2121111229. The reversal of 2121111221 is 1221111212.

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 2121111221 - 2² = 2121111217 is a prime.

It is a super-2 number, since 2×2121111221² = 8998225623704221682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2121111196 and 2121111205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121111229) 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, 131696 + ... + 146921.

It is an arithmetic number, because the mean of its divisors is an integer number (277503528).

Almost surely, 2^2121111221 is an apocalyptic number.

It is an amenable number.

2121111221 is a deficient number, since it is larger than the sum of its proper divisors (98917003).

2121111221 is a wasteful number, since it uses less digits than its factorization.

2121111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278971.

The product of its digits is 16, while the sum is 14.

The square root of 2121111221 is about 46055.5232409751. The cubic root of 2121111221 is about 1284.8560697145.

Adding to 2121111221 its reverse (1221111212), we get a palindrome (3342222433).

Subtracting from 2121111221 its reverse (1221111212), we obtain a palindrome (900000009).

The spelling of 2121111221 in words is "two billion, one hundred twenty-one million, one hundred eleven thousand, two hundred twenty-one".