A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3057300 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 25 30 36 43 45 50 60 75 79 86 90 100 129 150 158 172 180 215 225 237 258 300 316 387 395 430 450 474 516 645 711 774 790 860 900 948 1,075 1,185 1,290 1,422 1,548 1,580 1,935 1,975 2,150 2,370 2,580 2,844 3,225 3,397 3,555 3,870 3,950 4,300 4,740 5,925 6,450 6,794 7,110 7,740 7,900 9,675 10,191 11,850 12,900 13,588 14,220 16,985 17,775 19,350 20,382 23,700 30,573 33,970 35,550 38,700 40,764 50,955 61,146 67,940 71,100 84,925 101,910 122,292 152,865 169,850 203,820 254,775 305,730 339,700 509,550 611,460 764,325 1,019,100 1,528,650 and 3,057,300, with no remainder.
Since 3,057,300 cannot be divided by just 1 and 3,057,300, it is not a prime number.