A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3122080 can be evenly divided by 1 2 4 5 8 10 13 16 19 20 26 32 38 40 52 65 76 79 80 95 104 130 152 158 160 190 208 247 260 304 316 380 395 416 494 520 608 632 760 790 988 1,027 1,040 1,235 1,264 1,501 1,520 1,580 1,976 2,054 2,080 2,470 2,528 3,002 3,040 3,160 3,952 4,108 4,940 5,135 6,004 6,320 7,505 7,904 8,216 9,880 10,270 12,008 12,640 15,010 16,432 19,513 19,760 20,540 24,016 30,020 32,864 39,026 39,520 41,080 48,032 60,040 78,052 82,160 97,565 120,080 156,104 164,320 195,130 240,160 312,208 390,260 624,416 780,520 1,561,040 and 3,122,080, with no remainder.
Since 3,122,080 cannot be divided by just 1 and 3,122,080, it is not a prime number.