This puzzle was originally published in October. If leaves seem inappropriate, just replace them with mosquitos. What? You love leaves?
That backyard of yours is just full of leaves: abcd of them to be precise. Given the clues following, how many leaves are there?
1) There is exactly one pair of digits that is the same.
2) Every digit is evenly divisible by every smaller digit in the number.
3) The solution’s arrangement of the digits is the fourth-highest value arrangement.
4) None of the digits are prime.
5) The sum of all of the digits is even.
Submit your answer to Gene Wirchenko <firstname.lastname@example.org>. Your answer should be in the form of a proof. That means to show how your answer must be correct. The deadline is Wednesday, June 3, 2015 at noon Pacific Time. I will post the answer shortly after.