8321 has 4 divisors (see below), whose sum is σ = 8532.
Its totient is φ = 8112.
The previous prime is 8317. The next prime is 8329. The reversal of 8321 is 1238.
8321 = 642 + 652.
8321 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1238 = 2 ⋅619.
It can be written as a sum of positive squares in 2 ways, for example, as 4225 + 4096 = 65^2 + 64^2
It is a cyclic number.
It is not a de Polignac number, because 8321 - 22 = 8317 is a prime.
It is an alternating number because its digits alternate between even and odd.
It is a Duffinian number.
It is a nialpdrome in base 10.
It is a junction number, because it is equal to n+sod(n) for n = 8296 and 8305.
It is not an unprimeable number, because it can be changed into a prime (8329) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (3) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26 + ... + 131.
It is an arithmetic number, because the mean of its divisors is an integer number (2133).
It is a Proth number, since it is equal to 65 ⋅ 27 + 1 and 65 < 27.
It is a Poulet number, since it divides 28320-1.
28321 is an apocalyptic number.
8321 is the 53-rd octagonal number.
8321 is the 65-th centered square number.
It is an amenable number.
8321 is a deficient number, since it is larger than the sum of its proper divisors (211).
8321 is a wasteful number, since it uses less digits than its factorization.
8321 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 210.
The product of its digits is 48, while the sum is 14.
The square root of 8321 is about 91.2195154558.
The cubic root of 8321 is about 20.2639998703.
Adding to 8321 its reverse (1238), we get a palindrome (9559).
The spelling of 8321 in words is "eight thousand, three hundred twenty-one".