"What's your cell phone number?"

Translation: 你的手机号码是多少？

[Kyle808768]

No, for numbers, Even when not used for counting use 多少。 keep in mind not everything can be directly translated

[Han336780]

Good to know!

[Flamezzz]

应该是“你的手机号码是什么” 因为 "多少" 是 “How many"