A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3778080 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 17 20 24 30 32 34 40 48 51 60 68 80 85 96 102 120 136 160 170 204 240 255 272 340 408 463 480 510 544 680 816 926 1,020 1,360 1,389 1,632 1,852 2,040 2,315 2,720 2,778 3,704 4,080 4,630 5,556 6,945 7,408 7,871 8,160 9,260 11,112 13,890 14,816 15,742 18,520 22,224 23,613 27,780 31,484 37,040 39,355 44,448 47,226 55,560 62,968 74,080 78,710 94,452 111,120 118,065 125,936 157,420 188,904 222,240 236,130 251,872 314,840 377,808 472,260 629,680 755,616 944,520 1,259,360 1,889,040 and 3,778,080, with no remainder.
Since 3,778,080 cannot be divided by just 1 and 3,778,080, it is not a prime number.