2123131221 has 6 divisors (see below), whose sum is σ = 3066745110. Its totient is φ = 1415420808.

The previous prime is 2123131211. The next prime is 2123131229. The reversal of 2123131221 is 1221313212.

It can be written as a sum of positive squares in only one way, i.e., 1138050225 + 985080996 = 33735^2 + 31386^2 .

It is not a de Polignac number, because 2123131221 - 2¹⁷ = 2123000149 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2123131194 and 2123131203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2123131229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 117951726 + ... + 117951743.

It is an arithmetic number, because the mean of its divisors is an integer number (511124185).

Almost surely, 2^2123131221 is an apocalyptic number.

It is an amenable number.

2123131221 is a deficient number, since it is larger than the sum of its proper divisors (943613889).

2123131221 is a wasteful number, since it uses less digits than its factorization.

2123131221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235903475 (or 235903472 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 2123131221 is about 46077.4480738680. The cubic root of 2123131221 is about 1285.2638097353.

Adding to 2123131221 its reverse (1221313212), we get a palindrome (3344444433).

The spelling of 2123131221 in words is "two billion, one hundred twenty-three million, one hundred thirty-one thousand, two hundred twenty-one".