DB design, integer or string?

I have a long number , as a “secret code”. It’s 18 digits.

Shall I save it as an Integer or as a string in the database!?

<!-- OwnerSecretCode: 271464580357124432 -->

I answer myself!

strOwnerSecretCode varchar(20)

I also had the boolean question, but I think the answer can be found on the link as well! :slight_smile: