0516
The number is on the typewriter, "516". It is the combination (0516) to the secret room in the Captain's Quarters atop the Hub.
There is no password, but the combination for the safe is 0516.
The number "0516" on the spinning dial lock will open the secret compartment in Captain Ziggs' quarters atop the Hub. The number is revealed in the Mayor's office atop the Center. (Using the switch on the Cantina, the extension arm, and the multi-tool to open the skylight.)0516
its in the museum on mainstreet of steamworks island :)
The combination for the painting in Ziggs' room is 0516
It's Steamworks Island #14th Island
(The solution is at the related question "How do you beat Steamworks Island")
the crab on steamworks island is next to the living quarters
The only reason you need to go there is to get the "special number" that Captain Ziggs uses as his combination in his quarters. It is on the desk :the number 516 is translated into "0516" to open the secret closet.
You go to Steamworks and head to the museum and there is the Deogen
To get to the drawbridge, you go to the right of the Hub all the way to the edge of the scene. You get the key for it in Captain Ziggs' cabin.
there are 2 keys that i am aware of one under the crab then the other is in captain ziggs secret passage