Will an iPhone still have a phone number even if it has no sim card?

Will an iPhone still have a phone number even if it has no sim card? - 1

No, the number follows the SIM, not the phone. At least on a GSM phone.

CDMA carrier phones may not work that way, they didn't used to, the number was tied to the phone itself and the SIM was only for 4G data access. That may have changed, I haven't looked into it in a couple years.

No…

The SIM card is what gives it (or any phone) its phone number.