According to the International Federation of Actors (FIA), there are an estimated 10 million actors in the world. This number includes both professional and non-professional actors, and it is based on data from FIA's member organizations in over 100 countries.
Another estimate comes from the United Nations Educational, Scientific and Cultural Organization (UNESCO). UNESCO estimates that there are around 2.3 million actors worldwide. This number is based on data from the UNESCO Institute for Statistics, which collects data on cultural participation from over 150 countries.
It is important to note that these are just estimates, and the actual number of actors in the world may be higher or lower. Additionally, the number of actors can vary depending on how you define "actor" and what criteria you use to count them. For example, some sources may only count professional actors, while others may include both professional and non-professional actors.