You can convert numeric values to characters by using the TO_CHAR() function as shown in the following examples:

SELECT TO_CHAR(4123.4570) FROM DUAL

123.457

SELECT TO_CHAR(4123.457, '$9,999,999.99') FROM DUAL

$4,123.46

SELECT TO_CHAR(-4123.457, '9999999.99EEEE') FROM DUAL

-4.12E+03