2121322221 has 12 divisors (see below), whose sum is σ = 3146946972. Its totient is φ = 1375992576.

The previous prime is 2121322207. The next prime is 2121322253. The reversal of 2121322221 is 1222231212.

2121322221 is a `hidden beast` number, since 2 + 121 + 322 + 221 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1224020196 + 897302025 = 34986^2 + 29955^2 .

It is not a de Polignac number, because 2121322221 - 2¹⁰ = 2121321197 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2121322194 and 2121322203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121322121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3184836 + ... + 3185501.

It is an arithmetic number, because the mean of its divisors is an integer number (262245581).

Almost surely, 2^2121322221 is an apocalyptic number.

It is an amenable number.

2121322221 is a deficient number, since it is larger than the sum of its proper divisors (1025624751).

2121322221 is a wasteful number, since it uses less digits than its factorization.

2121322221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6370380 (or 6370377 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 2121322221 is about 46057.8138973182. The cubic root of 2121322221 is about 1284.8986724847.

Adding to 2121322221 its reverse (1222231212), we get a palindrome (3343553433).

It can be divided in two parts, 21213 and 22221, that added together give a palindrome (43434).

The spelling of 2121322221 in words is "two billion, one hundred twenty-one million, three hundred twenty-two thousand, two hundred twenty-one".