A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2145150 can be evenly divided by 1 2 3 5 6 7 9 10 14 15 18 21 25 27 30 35 42 45 50 54 63 70 75 90 105 126 135 150 175 189 210 225 227 270 315 350 378 450 454 525 630 675 681 945 1,050 1,135 1,350 1,362 1,575 1,589 1,890 2,043 2,270 3,150 3,178 3,405 4,086 4,725 4,767 5,675 6,129 6,810 7,945 9,450 9,534 10,215 11,350 12,258 14,301 15,890 17,025 20,430 23,835 28,602 30,645 34,050 39,725 42,903 47,670 51,075 61,290 71,505 79,450 85,806 102,150 119,175 143,010 153,225 214,515 238,350 306,450 357,525 429,030 715,050 1,072,575 and 2,145,150, with no remainder.
Since 2,145,150 cannot be divided by just 1 and 2,145,150, it is not a prime number.