converting text field into number by condition

Hii All ,

I have  an issue in  Erasing Zeros in a String Field called KNDNR  its have  values of  000012328 , 000082613721 , 000029387672 , E74JL

I need to show numbers without  zeros .. and other show it normally

I used  This formula  " if  NumericText ({CUST_EVAL.KNDNR} [ 1 to 2])  then   Tonumber  ({CUST_EVAL.KNDNR} ) "   But it only appear the values that begin with zeros and other  values like E74jl   show it Zero ..  i need to show other values normally  any help