221331321 has 12 divisors (see below), whose sum is σ = 320795748. Its totient is φ = 147048864.

The previous prime is 221331293. The next prime is 221331337. The reversal of 221331321 is 123133122.

It can be written as a sum of positive squares in 2 ways, for example, as 197711721 + 23619600 = 14061^2 + 4860^2 .

It is not a de Polignac number, because 221331321 - 2¹⁷ = 221200249 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221331294 and 221331303.

It is not an unprimeable number, because it can be changed into a prime (221338321) 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 11 ways as a sum of consecutive naturals, for example, 39330 + ... + 44603.

It is an arithmetic number, because the mean of its divisors is an integer number (26732979).

Almost surely, 2^221331321 is an apocalyptic number.

It is an amenable number.

221331321 is a deficient number, since it is larger than the sum of its proper divisors (99464427).

221331321 is a wasteful number, since it uses less digits than its factorization.

221331321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84232 (or 84229 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 221331321 is about 14877.2081050176. The cubic root of 221331321 is about 604.8963426899.

Adding to 221331321 its reverse (123133122), we get a palindrome (344464443).

The spelling of 221331321 in words is "two hundred twenty-one million, three hundred thirty-one thousand, three hundred twenty-one".