Grid Clues (Numeric)

Across

1. Sweet square (2)
2. Talk about a slice of pie (1.5)
7. Grand total of 17A - 5D - inverse(18D) (4)
9. Palindrome with square digits (4)
11. 13D taken up by nine (4)
13. No German heard after square one (4)
15. Even odds (2-2)
17. When Star Wars (and I) debuted in Waterloo (4)
20. Pythagorean triple (2,2,2)
21. See 14 Down

Down

1. Binary blackjack (5)
3. High time (2)
4. Disgusting quantity (3)
5. Two odd numbers to call in an emergency (3)
6. Book 'em, Dan-o (1-1)
8. Bonded agent (3)
10. Highway 191 hexed (3)
12. One for nothing (3)
13. Countdown (3)
14. Toronto Pizza Pizza (3-2-2)
15. Has Levis (3)
16. Prime whose sum of digits is also prime (3)
18. Some bottles of beer for the Great One (2)
19. Baker's dozen (2)