Find the 4 code number

123
Across
  1. 2. How old Hollow is divided by 4
  2. 3. I am an odd number, but if you take away my very first letter, I become even. What number am I?
Down
  1. 1. The day of the coronation
  2. 2. I am the total number of human senses. Subtract me from twelve, and you get seven. Divide a decade by two, and I remain. What number am I?