Comment by OJFord
5 years ago
Or to be really pedantic, 'is currently assigned a particular' phone number.
Since you can change phone number without changing SIM (I don't know if it's global, but in the UK you just text a certain number for a transfer 'PAC' code) and clone them.
It's harder than that in the US, but it's possible. Mostly it depends on the carrier's policy.