A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1983828 can be evenly divided by 1 2 3 4 6 7 11 12 14 19 21 22 28 33 38 42 44 57 66 76 77 84 113 114 132 133 154 209 226 228 231 266 308 339 399 418 452 462 532 627 678 791 798 836 924 1,243 1,254 1,356 1,463 1,582 1,596 2,147 2,373 2,486 2,508 2,926 3,164 3,729 4,294 4,389 4,746 4,972 5,852 6,441 7,458 8,588 8,701 8,778 9,492 12,882 14,916 15,029 17,402 17,556 23,617 25,764 26,103 30,058 34,804 45,087 47,234 52,206 60,116 70,851 90,174 94,468 104,412 141,702 165,319 180,348 283,404 330,638 495,957 661,276 991,914 and 1,983,828, with no remainder.
Since 1,983,828 cannot be divided by just 1 and 1,983,828, it is not a prime number.