There is no single, definitive number of Katibeen e Wahi. While some sources mention specific names, like Zaid ibn Thabit, Muawiyah ibn Abi Sufyan, and Uthman ibn Affan, others don't provide a specific count.
It's important to remember that the process of recording the Quran was not a singular event. Revelations were received over 23 years, with different individuals writing down the verses at different times and in different locations.
Therefore, it's difficult to determine a precise number of Katibeen e Wahi.