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:
... and the median income for a family is $67,375. Males have a median income of $50,715 versus $34,301 for females. The per capita income for the town is $23,233. 6.2% ...