Create Random Number up to 50 Digits and Store in Varchar

Does anyone have code; looking for a random number function generator. I would just supply with a variable length @NumberLength = 50, etc. It can create numbers up to 50 digits, and store in varchar. (Bigint does not store this high) I am using Floor Rand, Floor, NewId(), still not receiving answer, that exceeds 12 digits. If anyone has a solution, that would be great. I need to randomize a column in table. Thank you, Note: Needs to be in a function, functions cannot accept NewID or rand() for some reason, so I sometimes utilize views. If random number is used again, no issue, we can have little bit repetition.