There are many different numbering schemes for assigning numbers to entities. These generally require an agreed set of rules, or a central coordinator.
Numbering schemes include:
The E.164 numbering plan for telephone numbers, including:
... of 2000, there are 5,400 people, 1,693 households, and 1,286 families residing in the town. The population density is 387.5/km² (1,003.8/mi²). There are ...