The number 36 has an intimate connection to the number 6. Six, multiplied by it's self equals 36. Multiply 36 by 6 again and the result is 216. 36x12=432, and 432 is 216x2. Adding every number from 1 through 36 yields 666.
The Magic Square of the Sun (see image) numbers from 1 through 36. Each of it's rows and columns, as well as the diagonals, add to 111. Six (row or columns) multiplied by 111 equals 666. There is also a connection here with the number 74 as there are 9 "squares" (4 numbers at each corner of a square or rectangle arrangment of numbers from this grid) which add to 74, and 9x74=666.