The term "cell phone number" can be replaced with a few different synonyms to add some variety to your vocabulary. For example, "mobile phone number" is essentially the same thing and just as widely recognized. If you want to be more specific, you could use "wireless phone number" or "smartphone number." "Handset number" is another option for those who want to avoid using the word "phone." Additionally, if you're referring to a specific type of phone service, you could try "GSM number" or "CDMA number," depending on the network used. Regardless of which synonym you choose, make sure it's clear and easy for people to understand.