Special Date format conversation

Hi Guys, I have a dataset where the date format is a whole number, but - it starts from 01Jan1972 as a day 1, 02Jan1972 is shown as day 2 etc. today, 05Sep2029 ias shows as date 18876 

In practice it counts the pasing days since 01Jan1972 (including 01Jan1972). . How can I convert these dates to ta real date format in Power Query ? (or in DAX if Power Query is not possible )