1. I am a 6 digit whole number.

  2. Half of my digits are 2's.

  3. Half of my digits are 1's.

  4. I am divisible by 3.

  5. I am an odd number.

  6. I am divisible by 9.

  7. My digits alternate.

  8. I am greater than 200,000.

  9. My hundreds digit is less than 2.

  10. My tens digit is 2.


      Who am I?











Answer: I am 212,121.
The solution can be determined by clue 7.