title: Is a credit/debit card number numeric or an integer?
body: <p>Since a number can also be a decimal this makes me think that a CC number should be an integer. This would make sense as I don't think any credit cards start with 0 and since they all follow the same sort of pattern:</p>
  
  <p>4444333322221111</p>
  
  <p>So I guess they're an integer but I'm not too sure what international cards are like? Do any start with 0?</p>
  
  <p><strong>Update</strong></p>
  
  <p>Thanks for all your responses. It's less to store them (in fact I'd only store the last 4 numbers) and more to do a quick validation check. Regardless, I'd just treat it as an integer for validation, i.e. making sure that it's between 13-16 digits in length and always never a decimal.</p>