A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3048540 can be evenly divided by 1 2 3 4 5 6 10 11 12 15 20 22 30 31 33 44 55 60 62 66 93 110 124 132 149 155 165 186 220 298 310 330 341 372 447 465 596 620 660 682 745 894 930 1,023 1,364 1,490 1,639 1,705 1,788 1,860 2,046 2,235 2,980 3,278 3,410 4,092 4,470 4,619 4,917 5,115 6,556 6,820 8,195 8,940 9,238 9,834 10,230 13,857 16,390 18,476 19,668 20,460 23,095 24,585 27,714 32,780 46,190 49,170 50,809 55,428 69,285 92,380 98,340 101,618 138,570 152,427 203,236 254,045 277,140 304,854 508,090 609,708 762,135 1,016,180 1,524,270 and 3,048,540, with no remainder.
Since 3,048,540 cannot be divided by just 1 and 3,048,540, it is not a prime number.