217 = 7 x 31.
217 is the ninth centered hexagonal (hex) number.
47 and 89 are primes, as is their concatenation: 4789. Inserting 0 between them transforms the prime into a power: 47089 = 2172.
217 is 1001 in base 6 and 161 in base 12.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkzUEmc0oa3LxPuGgWjv37cPQ1GwvkMudYHZcsVh1fRT-PvBrsQRm0ybIK7yiWpR1MD-xAJbZ0CZ4Mqn7lU2Vq1392gFLcvzeCr9yQ_jsjQ9VYllDJNifg8iHsd5H8uMcbzFxvYckvBlc/s200/n0217.jpg)
217 is the telephone area code covering much of central Illinois.
Source: Prime Curios!