The largest six digit number period is 999999. The largest number meeting your criteria is 998949.
Greatest: 989949 Least: 100000
987654
999
In order to get the greatest number we want to try and get the biggest possible numbers in the hundred thousands, ten thousands and thousand places. There is no rule against the hundred thousands digit being 9 so it must be 9. The ten thousand digit needs to be twice the tens so it must be 8 while the tens is 4. The thousands digit is divided by the units, and the number is even. So thousands must be 6 and the units must be 2. Thus the hundreds must be 7. The number is 986,742
Add the two greatest possible four digit numbers. 9999 + 9999
smallest=1234 greatest=4321
Th e greatest 4-digit even number is 9,998 .
9998
998
998
It is: 97
3897