217321 has 8 divisors (see below), whose sum is σ = 238280. Its totient is φ = 196992.

The previous prime is 217319. The next prime is 217333. The reversal of 217321 is 123712.

It is a happy number.

217321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 48400 + 168921 = 220^2 + 411^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 217321 - 2¹ = 217319 is a prime.

It is a Duffinian number.

217321 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 217295 and 217304.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217351) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 835 + ... + 1063.

It is an arithmetic number, because the mean of its divisors is an integer number (29785).

2²¹⁷³²¹ is an apocalyptic number.

It is an amenable number.

217321 is a deficient number, since it is larger than the sum of its proper divisors (20959).

217321 is a wasteful number, since it uses less digits than its factorization.

217321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315.

The product of its digits is 84, while the sum is 16.

The square root of 217321 is about 466.1770050099. The cubic root of 217321 is about 60.1220663100.

The spelling of 217321 in words is "two hundred seventeen thousand, three hundred twenty-one", and thus it is an iban number.