A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3046740 can be evenly divided by 1 2 3 4 5 6 10 12 15 17 20 29 30 34 51 58 60 68 85 87 102 103 116 145 170 174 204 206 255 290 309 340 348 412 435 493 510 515 580 618 870 986 1,020 1,030 1,236 1,479 1,545 1,740 1,751 1,972 2,060 2,465 2,958 2,987 3,090 3,502 4,930 5,253 5,916 5,974 6,180 7,004 7,395 8,755 8,961 9,860 10,506 11,948 14,790 14,935 17,510 17,922 21,012 26,265 29,580 29,870 35,020 35,844 44,805 50,779 52,530 59,740 89,610 101,558 105,060 152,337 179,220 203,116 253,895 304,674 507,790 609,348 761,685 1,015,580 1,523,370 and 3,046,740, with no remainder.
Since 3,046,740 cannot be divided by just 1 and 3,046,740, it is not a prime number.