title: How could I encode a long number using uppercase letters and numbers to make it shorter to type?
body: <p>Is there a way I could encode a long number (e.g. 12349874529768521) as lower-case letters AND numbers for the purposes of reducing its length?  The idea is that a user might have a long number on a piece of paper. </p>
  
  <p>It seems to me that if there are more symbols available, that the resulting number could be made shorter. So I'm looking for something like hexadecimal but using the larger symbol space of A-Z instead of just A-F.</p>
  
  <p>This would be in C# (if it matters)</p>