A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5596020 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 27 30 36 43 45 54 60 86 90 108 129 135 172 180 215 241 258 270 387 430 482 516 540 645 723 774 860 964 1,161 1,205 1,290 1,446 1,548 1,935 2,169 2,322 2,410 2,580 2,892 3,615 3,870 4,338 4,644 4,820 5,805 6,507 7,230 7,740 8,676 10,363 10,845 11,610 13,014 14,460 20,726 21,690 23,220 26,028 31,089 32,535 41,452 43,380 51,815 62,178 65,070 93,267 103,630 124,356 130,140 155,445 186,534 207,260 279,801 310,890 373,068 466,335 559,602 621,780 932,670 1,119,204 1,399,005 1,865,340 2,798,010 and 5,596,020, with no remainder.
Since 5,596,020 cannot be divided by just 1 and 5,596,020, it is not a prime number.