A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1222020 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 27 30 31 36 45 54 60 62 73 90 93 108 124 135 146 155 180 186 219 270 279 292 310 365 372 438 465 540 558 620 657 730 837 876 930 1,095 1,116 1,314 1,395 1,460 1,674 1,860 1,971 2,190 2,263 2,628 2,790 3,285 3,348 3,942 4,185 4,380 4,526 5,580 6,570 6,789 7,884 8,370 9,052 9,855 11,315 13,140 13,578 16,740 19,710 20,367 22,630 27,156 33,945 39,420 40,734 45,260 61,101 67,890 81,468 101,835 122,202 135,780 203,670 244,404 305,505 407,340 611,010 and 1,222,020, with no remainder.
Since 1,222,020 cannot be divided by just 1 and 1,222,020, it is not a prime number.