221321 has 4 divisors (see below), whose sum is σ = 226512. Its totient is φ = 216132.

The previous prime is 221317. The next prime is 221327. The reversal of 221321 is 123122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 123122 = 2 ⋅61561.

It is a cyclic number.

It is not a de Polignac number, because 221321 - 2² = 221317 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (221327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2531 + ... + 2616.

It is an arithmetic number, because the mean of its divisors is an integer number (56628).

2²²¹³²¹ is an apocalyptic number.

It is an amenable number.

221321 is a deficient number, since it is larger than the sum of its proper divisors (5191).

221321 is an equidigital number, since it uses as much as digits as its factorization.

221321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5190.

The product of its digits is 24, while the sum is 11.

The square root of 221321 is about 470.4476591503. The cubic root of 221321 is about 60.4886940146.

Adding to 221321 its reverse (123122), we get a palindrome (344443).

The spelling of 221321 in words is "two hundred twenty-one thousand, three hundred twenty-one", and thus it is an iban number.