A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3889080 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 13 15 18 20 24 26 27 30 36 39 40 45 52 54 60 65 72 78 90 104 108 117 120 130 135 156 180 195 216 234 260 270 277 312 351 360 390 468 520 540 554 585 702 780 831 936 1,080 1,108 1,170 1,385 1,404 1,560 1,662 1,755 2,216 2,340 2,493 2,770 2,808 3,324 3,510 3,601 4,155 4,680 4,986 5,540 6,648 7,020 7,202 7,479 8,310 9,972 10,803 11,080 12,465 14,040 14,404 14,958 16,620 18,005 19,944 21,606 24,930 28,808 29,916 32,409 33,240 36,010 37,395 43,212 49,860 54,015 59,832 64,818 72,020 74,790 86,424 97,227 99,720 108,030 129,636 144,040 149,580 162,045 194,454 216,060 259,272 299,160 324,090 388,908 432,120 486,135 648,180 777,816 972,270 1,296,360 1,944,540 and 3,889,080, with no remainder.
Since 3,889,080 cannot be divided by just 1 and 3,889,080, it is not a prime number.