A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8206275 can be evenly divided by 1 3 5 7 11 15 21 25 29 33 35 49 55 75 77 87 105 145 147 165 175 203 231 245 275 319 343 385 435 525 539 609 725 735 825 957 1,015 1,029 1,155 1,225 1,421 1,595 1,617 1,715 1,925 2,175 2,233 2,695 3,045 3,675 3,773 4,263 4,785 5,075 5,145 5,775 6,699 7,105 7,975 8,085 8,575 9,947 11,165 11,319 13,475 15,225 15,631 18,865 21,315 23,925 25,725 29,841 33,495 35,525 40,425 46,893 49,735 55,825 56,595 78,155 94,325 106,575 109,417 149,205 167,475 234,465 248,675 282,975 328,251 390,775 547,085 746,025 1,172,325 1,641,255 2,735,425 and 8,206,275, with no remainder.
Since 8,206,275 cannot be divided by just 1 and 8,206,275, it is not a prime number.