Yes, but …
But under Article 14 you have to inform the data subject within 30 days, that you are processing their data and where you got that data from. This also includes data that you have gathered from public sources if that processing is not yet known to the data subjects.
Additionally, you have to obey to the rules of the Telecommunications Act when contacting potential customers.
Furthermore, it has to be easy for the data subjects to object to this kind of processing.