A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2242560 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 24 30 32 40 48 60 64 73 80 96 120 128 146 160 192 219 240 256 292 320 365 384 438 480 512 584 640 730 768 876 960 1,024 1,095 1,168 1,280 1,460 1,536 1,752 1,920 2,048 2,190 2,336 2,560 2,920 3,072 3,504 3,840 4,380 4,672 5,120 5,840 6,144 7,008 7,680 8,760 9,344 10,240 11,680 14,016 15,360 17,520 18,688 23,360 28,032 30,720 35,040 37,376 46,720 56,064 70,080 74,752 93,440 112,128 140,160 149,504 186,880 224,256 280,320 373,760 448,512 560,640 747,520 1,121,280 and 2,242,560, with no remainder.
Since 2,242,560 cannot be divided by just 1 and 2,242,560, it is not a prime number.