As of my knowledge cutoff in September 2021, the exact number of members of the Prosperity Party (PP) in Ethiopia is not publicly available. The party was formed in 2019 by merging several political parties, including the Ethiopian People’s Revolutionary Democratic Front (EPRDF), which had a significant membership base. However, it is important to note that political party membership numbers can fluctuate over time due to various factors such as recruitment, attrition, and political dynamics.