more n more ques :P

haha..here got a few more questions for u guys :b not all math question...so...lets consider it as thinking skills questions.. ;P

1. What are the next two letters in this series: A E F H I K L M ?

2. Look at the number 8,549,176,320. What is special about this number?

3. How many letters are in the answer to this question?
HINT : Don't bother counting the letters in the phrase 'the answer to this question' - i already thought of
that, and its the incorrect answer! :p

4. solve this:

2 + 2 = 4
4 + 4 = 8
142 + 468 = 621
3762 + 8271 = ?

hehe..enjoy ya! ;p