You can use NUMWIDTH to prevent large numbers being displayed in scientific notation. First check the current value of NUMWIDTH:
SQL> show numwidth
numwidth 10
SQL>
Next, display a large number. As it is more than NUMWIDTH digits long, it appears in scientific notation:
SQL> select sum(bytes) from dba_data_files;
SUM(BYTES)
----------
1.2863E+11
SQL>
This will need a NUMWIDTH of 12 or more to be displayed as a normal number:
SQL> set numwidth 12
SQL> l
1* select sum(bytes) from dba_data_files
SQL> /
SUM(BYTES)
------------
128625672192
SQL>
