Develop a function that can set a prefix on every number

Hi,

Did anyone have a sample of function that can set a prefix on every number?

Let's say, format current number length is 10. My number is 28790. When i pass this 28790 to above function, it will return a 0000028790. When i pass 2897690 to above function, it will return a 0002897690.

Please help me.