SQL> create table tab1(col1 number,col2 number);

Table created.

SQL> select * from tab1;

no rows selected

datafile:(samp.dat)

3372756.881,5673423 
3330140.566,5691491 

control file:

LOAD DATA 
infile samp.dat
APPEND 
INTO TABLE tab1 
FIELDS TERMINATED BY "," optionally enclosed by '"'
TRAILING NULLCOLS 
( 
col1  , 
col2   ) 

SQL> select * from tab1;

      COL1       COL2
---------- ----------
3372756.88    5673423
3330140.57    5691491

SQL> select to_char(col1,'99999999.999'),col2 from tab1;

TO_CHAR(COL1,       COL2
------------- ----------
  3372756.881    5673423
  3330140.566    5691491