I started out as _ _ _,_ _ _

The 10,000 place has to be the biggest you can get. However, 9 isn’t an even number so I used 8., so the 10’s digit is a 4. The biggest prime number from 1-10 is 7, for the hundred thousands place. The thousands digit has to be the biggest number divisible by another number, which is 9, so the 1’s digit is a 3. The only place left is the hundreds place, and I used the biggest number i can get, 6.

A must be prime, so A can be 2,3,5,7. Choose biggest: A = 7.

B is twice E, so it must be even, Let B = 8, biggest even digit, so E is 4. Now we have N = 78CD4F.

C is divisible by F, make C as big as possible for C = 9. Now N = 789D4F.

D can be anything, biggest remaining digit is 6.

F must be a divisor of C, biggest one is 3.

So it looks like N = 789643.

8 is twice 4

7 is a prime number

6 is divisible by 1 ( 1 goes into 6 six times.)