A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5408480 can be evenly divided by 1 2 4 5 7 8 10 11 14 16 20 22 28 32 35 40 44 55 56 70 77 80 88 110 112 140 154 160 176 220 224 280 308 352 385 439 440 560 616 770 878 880 1,120 1,232 1,540 1,756 1,760 2,195 2,464 3,073 3,080 3,512 4,390 4,829 6,146 6,160 7,024 8,780 9,658 12,292 12,320 14,048 15,365 17,560 19,316 24,145 24,584 30,730 33,803 35,120 38,632 48,290 49,168 61,460 67,606 70,240 77,264 96,580 98,336 122,920 135,212 154,528 169,015 193,160 245,840 270,424 338,030 386,320 491,680 540,848 676,060 772,640 1,081,696 1,352,120 2,704,240 and 5,408,480, with no remainder.
Since 5,408,480 cannot be divided by just 1 and 5,408,480, it is not a prime number.