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 which 43.6% have children under the age of 18 living with them, 62.2% are married couples living together, 17.0% have a female householder with no husband present, and ...