Get the Code in Binary or in Dec

[gewhjhfkgad]

Hi there

I am trying to get the readed nubmer displayed in decimal or in binary.
Or the more important thing is to add the number 10'000'000 to the card number and send it again threw 2 other pins also threw the wiegand protocol.

I already was able to ready the correct number in hex with the library.
I think if i got the bits from the code i am able to ad the 10'000'000 and send this.

What im an not able to do is to convert the numbers or work with this.
The output is in hex and just printed to the monitor.
If i can store the number in a variable i think it it not hard to convert them into a binary.

I need to have an input to the arduino like this: 1234
And an output at the end with 10'001'234.
Just the readed card with the adition. I need to have the data in the accesscontrolsystem i have in this format.

Any Ideas, how to get this data and send it?

Many thanks in advanced for any help.