---
id: 5900f38f1000cf542c50fea2
challengeType: 5
title: 'Problem 35: Circular primes'
videoUrl: ''
localeTitle: 问题35：循环素数
---

## Description
<section id="description">这个数字197被称为循环素数，因为数字的所有旋转：197,971和719本身都是素数。在100：2,3,5,7,11,13,17,31,37,71,73,79和97之下有十三个这样的素数。在n下面有多少个圆形素数，而100 &lt;= n &lt; = 1000000？ </section>

## Instructions
<section id="instructions">
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>circularPrimes(100)</code>应该返回13。
    testString: 'assert(circularPrimes(100) == 13, "<code>circularPrimes(100)</code> should return 13.");'
  - text: <code>circularPrimes(100000)</code>应该返回43。
    testString: 'assert(circularPrimes(100000) == 43, "<code>circularPrimes(100000)</code> should return 43.");'
  - text: <code>circularPrimes(250000)</code>应该返回45。
    testString: 'assert(circularPrimes(250000) == 45, "<code>circularPrimes(250000)</code> should return 45.");'
  - text: <code>circularPrimes(500000)</code>应该返回49。
    testString: 'assert(circularPrimes(500000) == 49, "<code>circularPrimes(500000)</code> should return 49.");'
  - text: <code>circularPrimes(750000)</code>应该返回49。
    testString: 'assert(circularPrimes(750000) == 49, "<code>circularPrimes(750000)</code> should return 49.");'
  - text: <code>circularPrimes(1000000)</code>应该返回55。
    testString: 'assert(circularPrimes(1000000) == 55, "<code>circularPrimes(1000000)</code> should return 55.");'

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function circularPrimes(n) {
  // Good luck!
  return n;
}

circularPrimes(1000000);

```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```
</section>