'I have a mobile' is an alternative translation since 'mobile' is a synonym for 'cell phone' (at least in the UK).
Other word for 'cell phone', a bit more formal one would be 'matkapuhelin'
älypuhelin = a smartphone
That was the first one I was shown. Randomness is random.
Mobile is also Kännykkä
I have also heard "fone" or "phone" (no clue how it would ne written) by youth
"Fone" is just incorrect, and while many people say "Phone" short for "Cellphone" it isn't specific enough.