The number 1,371,216 can be evenly divided by 1 2 3 4 6 7 8 11 12 14 16 21 22 24 28 33 42 44 48 49 53 56 66 77 84 88 98 106 112 132 147 154 159 168 176 196 212 231 264 294 308 318 336 371 392 424 462 528 539 583 588 616 636 742 784 848 924 1,078 1,113 1,166 1,176 1,232 1,272 1,484 1,617 1,749 1,848 2,156 2,226 2,332 2,352 2,544 2,597 2,968 3,234 3,498 3,696 4,081 4,312 4,452 4,664 5,194 5,936 6,468 6,996 7,791 8,162 8,624 8,904 9,328 10,388 12,243 12,936 13,992 15,582 16,324 17,808 20,776 24,486 25,872 27,984 28,567 31,164 32,648 41,552 48,972 57,134 62,328 65,296 85,701 97,944 114,268 124,656 171,402 195,888 228,536 342,804 457,072 685,608 and 1,371,216, with no remainder.
Since 1,371,216 cannot be divided by just 1 and 1,371,216, it is a composite number.