A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5551200 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 25 27 30 32 36 40 45 48 50 54 60 72 75 80 90 96 100 108 120 135 144 150 160 180 200 216 225 240 257 270 288 300 360 400 432 450 480 514 540 600 675 720 771 800 864 900 1,028 1,080 1,200 1,285 1,350 1,440 1,542 1,800 2,056 2,160 2,313 2,400 2,570 2,700 3,084 3,600 3,855 4,112 4,320 4,626 5,140 5,400 6,168 6,425 6,939 7,200 7,710 8,224 9,252 10,280 10,800 11,565 12,336 12,850 13,878 15,420 18,504 19,275 20,560 21,600 23,130 24,672 25,700 27,756 30,840 34,695 37,008 38,550 41,120 46,260 51,400 55,512 57,825 61,680 69,390 74,016 77,100 92,520 102,800 111,024 115,650 123,360 138,780 154,200 173,475 185,040 205,600 222,048 231,300 277,560 308,400 346,950 370,080 462,600 555,120 616,800 693,900 925,200 1,110,240 1,387,800 1,850,400 2,775,600 and 5,551,200, with no remainder.
Since 5,551,200 cannot be divided by just 1 and 5,551,200, it is not a prime number.