A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2679120 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 30 36 40 45 48 60 61 72 80 90 120 122 144 180 183 240 244 305 360 366 488 549 610 720 732 915 976 1,098 1,220 1,464 1,830 2,196 2,440 2,745 2,928 3,660 3,721 4,392 4,880 5,490 7,320 7,442 8,784 10,980 11,163 14,640 14,884 18,605 21,960 22,326 29,768 33,489 37,210 43,920 44,652 55,815 59,536 66,978 74,420 89,304 111,630 133,956 148,840 167,445 178,608 223,260 267,912 297,680 334,890 446,520 535,824 669,780 893,040 1,339,560 and 2,679,120, with no remainder.
Since 2,679,120 cannot be divided by just 1 and 2,679,120, it is not a prime number.