How to convert scientific number to its original form (In Proc SQL)

I have a column in my table called policykey, where data is supposed to be something along the lines of 20000000000000012.

Unfortunately, the output always comes out as 2e-15 or something to that effect.

How do I convert it back to its original format?

Is it;
Policy_key format=18.
Table name?

I've been googling and I'm not understanding the solution. Some use 'best', some use 'format', and I don't understand the different codes. I,e format = 18, etc etc