A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3052860 can be evenly divided by 1 2 3 4 5 6 10 12 15 17 20 30 34 41 51 60 68 73 82 85 102 123 146 164 170 204 205 219 246 255 292 340 365 410 438 492 510 615 697 730 820 876 1,020 1,095 1,230 1,241 1,394 1,460 2,091 2,190 2,460 2,482 2,788 2,993 3,485 3,723 4,182 4,380 4,964 5,986 6,205 6,970 7,446 8,364 8,979 10,455 11,972 12,410 13,940 14,892 14,965 17,958 18,615 20,910 24,820 29,930 35,916 37,230 41,820 44,895 50,881 59,860 74,460 89,790 101,762 152,643 179,580 203,524 254,405 305,286 508,810 610,572 763,215 1,017,620 1,526,430 and 3,052,860, with no remainder.
Since 3,052,860 cannot be divided by just 1 and 3,052,860, it is not a prime number.