Cast from Integer to Character in oracle

I have one query in DB2 which i want to convert it into Oracle

Query is:

Select CAST (CHAR(CAST(A.MAXVALUE AS BIGINT))AS VARCHAR(255)) "ELEMENT_VALUE" FROM TABLE TEST A;

I am not able to run this query in oracle please help.In oracle I can convert Integer directly to Varchar like

CAST (A.MAXVALUE AS VACHAR(255)) but then i need to change same thing in DB2 but DB2 not allows cast from Integer to Varchar

So i want query in a format which will run on both Oracle and DB2

Please help Thanks in Advance