The number 37 is a very interesting number. It is a prime number so
divisible by itself and 1. But it is the only prime number which can do the following

111 ÷ 37 = 3
222 ÷ 37 = 6
333 ÷ 37 = 9
444 ÷ 37 = 12
555 ÷ 37 = 15
666 ÷ 37 = 18

What will you get when 777, 888 and 999 are divided by 37 ?