817321 has 2 divisors, whose sum is σ = 817322. Its totient is φ = 817320.

The previous prime is 817319. The next prime is 817331. The reversal of 817321 is 123718.

817321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 541696 + 275625 = 736^2 + 525^2 .

It is a cyclic number.

It is not a de Polignac number, because 817321 - 2¹ = 817319 is a prime.

Together with 817319, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 817292 and 817301.

It is not a weakly prime, because it can be changed into another prime (817331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408660 + 408661.

It is an arithmetic number, because the mean of its divisors is an integer number (408661).

2⁸¹⁷³²¹ is an apocalyptic number.

It is an amenable number.

817321 is a deficient number, since it is larger than the sum of its proper divisors (1).

817321 is an equidigital number, since it uses as much as digits as its factorization.

817321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336, while the sum is 22.

The square root of 817321 is about 904.0580733559. The cubic root of 817321 is about 93.4969734119.

The spelling of 817321 in words is "eight hundred seventeen thousand, three hundred twenty-one".