Date: Use ordinal number.
Example: 1 October 1 day:1October1,1October 1st,1October 1Oct,/kloc-. October 1Oct can be written in abbreviated form.
Reading: October 1st or October 1st.
Extended data:
Month is a proper noun, and there are abbreviations besides months:
January to January. January
February to February. February
March to March. March
April to April. April
August to August. August
September to September. September
October to October. October
1 1 month to 1 1 month. November
December to December. December
Note: The dot after the abbreviated form cannot be omitted, because it is a symbol indicating the abbreviated form.