2:21 is a semiprime time as 221 is a semiprime number, since 221 is the product of the prime numbers 13 and 17.

1. Determine the total number of semiprime times in 12 hours.
2. Determine the total number of semiprime times in 24 hours.

Notes:
• A definition of semiprime is provided in this location.
• Thanks go to Math Man for inspiring this puzzle.