The best pronounced sentence so far (with diacritics too)
There is a mistake in it actually. It should be رَقْم with a ْ on the ق
The "of" form of the sentences must also be recognized as correct, for example: the phone number of the engineer
How does the word 'phone number' work? Because it forms a genitive with engineer, but commonly any adjective is placed after the last part of the genitive connection, but that's not the case here. Is phone something else than an adjective here?