Let me stick some spaces in some helpful places:
2018 01 21 . 15 30
20180121 means 21st January 2018, and 1530 is in 24-hour clock format, IE 3:30PM
Stardates in the Star Trek universe work in an entirely different way. Wikipedia has a good explanation on how they work.
Events on this stardate
Come and see Pixar's latest film with us: Coco. The story follows a 12-year-old boy named Miguel Rivera who is accidentally transported to the land of the dead, where he seeks the help of his deceased musician great-great-grandfather to return him to his family among the living.