8P of the SS – 8 planets of the Solar System
1M of the E – 1 Moon of the earth
1S of the SS – 1 Sun of the Solar System
60M in 1H – 60 minutes in 1 Hour
Monday has 6 letters , 1st day and 6+1 = 7
Tuesday has 7 letters , 2nd day and 7+2 = 9
………. and it is same for rest of the days.
Therefore , Sunday has 6 letters , 7th day and 6+7 = 13
So, Sunday = 6713