A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3706956 can be evenly divided by 1 2 3 4 6 9 11 12 18 22 23 33 36 37 44 46 66 69 74 92 99 111 121 132 138 148 198 207 222 242 253 276 333 363 396 407 414 444 484 506 666 726 759 814 828 851 1,012 1,089 1,221 1,332 1,452 1,518 1,628 1,702 2,178 2,277 2,442 2,553 2,783 3,036 3,404 3,663 4,356 4,477 4,554 4,884 5,106 5,566 7,326 7,659 8,349 8,954 9,108 9,361 10,212 11,132 13,431 14,652 15,318 16,698 17,908 18,722 25,047 26,862 28,083 30,636 33,396 37,444 40,293 50,094 53,724 56,166 80,586 84,249 100,188 102,971 112,332 161,172 168,498 205,942 308,913 336,996 411,884 617,826 926,739 1,235,652 1,853,478 and 3,706,956, with no remainder.
Since 3,706,956 cannot be divided by just 1 and 3,706,956, it is not a prime number.