there is no prove to show what day it is so there is no answer
July 21 1961 was a Friday.
September 21, 1961 was a Thursday.
May 21 1961 was a Sunday.
April 21, 1961 fell on a Friday.
October 21, 1961 fell on a Saturday.
21 August 1975 was a Thursday.
August 21 1996 was a Wednesday.
21 August 1933 was a Monday.
August 21, 1950 was a Monday.
August 21, 1978 was a Monday.
21 August 1945 was a Tuesday.
21 August 1942 was a Friday.