2215531321 has 4 divisors (see below), whose sum is σ = 2216811492. Its totient is φ = 2214251152.

The previous prime is 2215531319. The next prime is 2215531337. The reversal of 2215531321 is 1231355122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1231355122 = 2 ⋅615677561.

It can be written as a sum of positive squares in 2 ways, for example, as 1017610000 + 1197921321 = 31900^2 + 34611^2 .

It is a cyclic number.

It is not a de Polignac number, because 2215531321 - 2¹ = 2215531319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2215531301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 637486 + ... + 640951.

It is an arithmetic number, because the mean of its divisors is an integer number (554202873).

Almost surely, 2^2215531321 is an apocalyptic number.

It is an amenable number.

2215531321 is a deficient number, since it is larger than the sum of its proper divisors (1280171).

2215531321 is a wasteful number, since it uses less digits than its factorization.

2215531321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1280170.

The product of its digits is 1800, while the sum is 25.

The square root of 2215531321 is about 47069.4308548553. The cubic root of 2215531321 is about 1303.6448640916.

Adding to 2215531321 its reverse (1231355122), we get a palindrome (3446886443).

The spelling of 2215531321 in words is "two billion, two hundred fifteen million, five hundred thirty-one thousand, three hundred twenty-one".