A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 973440 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 13 15 16 18 20 24 26 30 32 36 39 40 45 48 52 60 64 65 72 78 80 90 96 104 117 120 128 130 144 156 160 169 180 192 195 208 234 240 260 288 312 320 338 360 384 390 416 468 480 507 520 576 585 624 640 676 720 780 832 845 936 960 1,014 1,040 1,152 1,170 1,248 1,352 1,440 1,521 1,560 1,664 1,690 1,872 1,920 2,028 2,080 2,340 2,496 2,535 2,704 2,880 3,042 3,120 3,380 3,744 4,056 4,160 4,680 4,992 5,070 5,408 5,760 6,084 6,240 6,760 7,488 7,605 8,112 8,320 9,360 10,140 10,816 12,168 12,480 13,520 14,976 15,210 16,224 18,720 20,280 21,632 24,336 24,960 27,040 30,420 32,448 37,440 40,560 48,672 54,080 60,840 64,896 74,880 81,120 97,344 108,160 121,680 162,240 194,688 243,360 324,480 486,720 and 973,440, with no remainder.
Since 973,440 cannot be divided by just 1 and 973,440, it is not a prime number.