A couple of days after the post, I was presented with millions of records having such numbers. The requirement being able to search through these numbers to get the records and get just one of them. As would other persons in my profession, I uploaded the data into a database on my local machine. I chose MS-SQL and used the SQL Server Management Studio (SMSS). Discussion on the choice of tool deserves a post on its own. The original file format was flat (see flat file format) occupying a little less than 4 GB but when loaded into the database it doubled and there my worries began.
Many times, I have seen developers write code for validating entries and they write very many if blocks or worse combine them with numerous switch cases. This approach would not have a problem but then more times than not, they need to be updated in certain periods when something new arises or for certain edge scenarios not originally considered.