I believe Android 16 is the Strongest Android. Powerlevel wise, comparing to the other androids.
Movie Timeline (Super Android 13!)
Super Android 13 )> 25,000,000
Series timeline (Android/Cell era)
Android 16 )> 30,000,000
Android 17 )> 23,000,000
Android 18 )> 23,000,000
Android 19 )> 10,000,000
Android 20 (Dr. Gero) )> 2,000,000
(Notice the higher the number of the android, the Weaker. It is this way in the series, the movie timeline is slightly different.)
(Now compared to the Super Saiyans and Cell.
Goku )> 2,500,000
Super Saiyan Goku )> 15,000,000
Trunks )> 2,000,000
Super Saiyan Trunks )> 12,000,000
Vegeta )> 3,000,000
Super Saiyan Vegeta )> 18,000,000
(First time Vegeta transformed he over powered all of the saiyans)
SSJ Goku (15,000,000) Vs. Android 16 (30,000,000)
that's suicide.
Cell (First appearence) 25,000,000 (Android 16 was a bit stronger than Cell when he first arrived)
Cell (after obsorbing millions of people) 31,000,000
Ascended Super Saiyans
___
Super Saiyan Vegeta )> 25,000,000
Super Vegeta )> 38,000,000
Super Saiyan Trunks )> 22,000,000
Super Trunks )> 37,500,000
Super Trunks (MAX) )> 45,000,000
(Trunks made a big mistake sacrificing speed for strength)
Cell
__
1st form Cell (MAX) )> 31,000,000
2nd form Cell (MAX) )> 36,000,000
Perfect Cell )> 40,000,000
Movie timeline (Super android 13)
Super Saiyan Goku )> 15,500,000
Goku )> 4,000,000
Super Saiyan Trunks )> 14,500,000
Trunks )> 3,500,000
Super Saiyan Vegeta )> 15,000,000
Vegeta )> 4,000,000
Android 13 )> 14,000,000
Android 14 )> 12,000,000
Android 15 )> 12,000,000
(Both Android 14 and 15 were completely even)
Don't compare movie timelines with series powerlevels. There all different.
Out of this information, it is clear Cell is infact and Android, and he is the most powerful
In all forms.
Android 16 )> 30,000,000
Cell (Stage 1) )> 25,000,000
Cell (Stage 1) (MAX power achieved) )> 31,000,000
Cell (Stage 2) )> 36,000,000 (Max: 37,000,000)
Perfect Cell )> 40,000,000
Ultimate Perfection (Cell : 45,000,000)
Pumped up Cell : 50,000,000
(sacrificed speed for strength)
If you count DragonBall GT then,
Android 17 is the strongest, since he fuses with himself, and becomes
Super 17
Super 17 )> 85,000,000
(was Super 17's power level)
Against Earth's forces
Super Saiyan Vegeta )> 55,000,000
Super Saiyan 2 Vegeta )> 77,000,000
Super Saiyan Trunks )> 43,000,000
Super Saiyan Goten )> 35,000,000
Super Saiyan Gohan )> 40,000,000
Super Saiyan 2 Gohan )> 65,000,000
Pan)> 40,000,000
DragonBall GT Strongest ANDROID:
Super 17 at 85,000,000
DragonBall Z Strongest Android:
Cell at 45,000,000