Transform a number into a sum of numbers

My request is a little bit strange and I cannot find tips elsewhere.

I will try to explain it clearly.

I have a number. (most of the time 5 or 6 digits long)

I need to transform it into a sum of 3 or 4 numbers that do not contain 0 and that have the same number of digits. And also that are different (random).

Ex:
Start number: 123456
Result: 16828 + 19283 + 87345

Start number: 654321
Result: 194849 + 134296 + 325176

Start number: 310116
Result: 78122 + 81364 + 65713 + 84917

My math brain reaches his limits so I cannot find a way to get that. :-)

I hope I'm clear.

Thanks in advance for your help.