217285 has 4 divisors (see below), whose sum is σ = 260748. Its totient is φ = 173824.

The previous prime is 217271. The next prime is 217307. The reversal of 217285 is 582712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 103041 + 114244 = 321^2 + 338^2 .

It is a cyclic number.

It is not a de Polignac number, because 217285 - 2⁵ = 217253 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21724 + ... + 21733.

It is an arithmetic number, because the mean of its divisors is an integer number (65187).

2²¹⁷²⁸⁵ is an apocalyptic number.

It is an amenable number.

217285 is a deficient number, since it is larger than the sum of its proper divisors (43463).

217285 is an equidigital number, since it uses as much as digits as its factorization.

217285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43462.

The product of its digits is 1120, while the sum is 25.

The square root of 217285 is about 466.1383914676. The cubic root of 217285 is about 60.1187463150.

Adding to 217285 its reverse (582712), we get a palindrome (799997).

The spelling of 217285 in words is "two hundred seventeen thousand, two hundred eighty-five".