Requirement to split the number value ,add a space and display with remaining values

Hello All,
I have an requirement to split the number ,modify it and display with remaining values.

e.g. the no is- 1234561
and we want to display it like this- 12 34561

Now the requirement is to split it from left to right till 5 digits ,add a space and display the remaining values.
I have tried using substr function but it did not work.
Can anyone guide me how to do that?

Thanks,
Joohi