Cognomen ปฐมบุตร (ปฐมบุตร 
, Phathombut , Prathombut ) , in the world, is a very rare surname. The surname ปฐมบุตร is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname. Likewise, ปฐมบุตร is the forename as well as the last name.