A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3525210 can be evenly divided by 1 2 3 5 6 9 10 13 15 18 23 26 30 39 45 46 65 69 78 90 115 117 130 131 138 195 207 230 234 262 299 345 390 393 414 585 598 655 690 786 897 1,035 1,170 1,179 1,310 1,495 1,703 1,794 1,965 2,070 2,358 2,691 2,990 3,013 3,406 3,930 4,485 5,109 5,382 5,895 6,026 8,515 8,970 9,039 10,218 11,790 13,455 15,065 15,327 17,030 18,078 25,545 26,910 27,117 30,130 30,654 39,169 45,195 51,090 54,234 76,635 78,338 90,390 117,507 135,585 153,270 195,845 235,014 271,170 352,521 391,690 587,535 705,042 1,175,070 1,762,605 and 3,525,210, with no remainder.
Since 3,525,210 cannot be divided by just 1 and 3,525,210, it is not a prime number.