Bismuth 209 facts

While investigating facts about Bismuth 209, I found out little known, but curios details like:

Bismuth 209 was long thought to be a stable isotope until scientists discovered it actually has a half life of 19 quintillion years

Despite being considered stable, Bismuth 209 undergoes alpha decay with a half life about a billion times longer than the estimated age of the universe. (1.9 x 10^19 years)

In my opinion, it is useful to put together a list of the most interesting details from trusted sources that I've come across. Here are 2 of the best facts about Bismuth 209 I managed to collect.