There are 6 stable isotopes. They are Se-74, Se-76, Se-77, Se-78, Se-80 and Se-82. Anon 

 What the hell are you talking about? This isn't the talk for selenium. You are mistaken BTW; Se-82 has a half life of 1.08 E20 y. Granted that is absurdly long but it still means that the isotope is radioactive (proton decay is another matter).