title: number divisible by 17?
body: <p>Given a large positive number of at most 1000 digits. You have to find out whether that number is divisible by 17 or not. 
  I know an algorithm which says multiply the last digit by 5 and subtract from the remaining number, if the resulting number is divisible by 17, then the number is divisible by 17. 
  Is there any more efficient method?</p>