ISO 14000 is an International Standard concerning the Environment Management System, while ISO 9000 is similarly concerned with Quality Management System.
Basically ISO 9000 is applied to manufacturing and services for achieving and maintaining consistant quality products or services, while ISO 14000 is for achieving and maintaining consistant environmental quality aspects.
I'm not precisely certain, but I do not believe the actual number itself has any significance. It is probably much like a street address, ECN #, procedure #, telephone # (you get the idea). It is more or less a number assigned to a standard to distinguish it from the next.
Of course I may be wrong, this is only my take on the question. However, a Wiki search gave me the following list of ISO Standards. Enjoy!
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