A = 1919191919 = 1900000000 + 19000000 + 190000 + 1900 + 19 = 19 * 100000000 + 19 * 1000000 + 19 * 10000 + 19 * 100 + 19 * 1 = 19 * (100000000 + 1000000 + 10000 + 100 + 1) = 19 * 101010101;
Аналогично:
B = 3737373737 = 37 * 101010101
A / B = 19 * 101010101 / (37 * 101010101) = 19 / 37.