Posted by A while back we had an AskTom question about arbitrary length addition and subtraction, and so I whipped a small PL./SQL in this post. A similar question came in recently about converting decimals to binary, but once again for decimals of arbitrary length.
So here’s a quick piece of PL/SQL for anyone wanting really a large number of bits 
SQL> create or replace
2 function dec_to_bit(p_decimal varchar2) return varchar2 is
3
4 l_num varchar2(4000) := p_decimal;
5 l_res varchar2(4000);
6 l_last_dig pls_integer;
7
8 function div2(p_dec varchar2) return varchar2 is
9 type integer_array is table of integer;
10 n1 integer_array := integer_array();
11 res integer_array := integer_array();
12 carry pls_integer := 0;
13 tmp pls_integer;
14 str varchar2(1000);
15 begin
16 for i in 1 .. length(p_dec) loop
17 n1.extend;
18 n1(i) := to_number(substr(p_dec,i,1));
19 end loop;
20 res.extend(n1.count);
21
22 for i in 1 .. n1.count
23 loop
24 str := str || trunc(((10*carry)+n1(i))/2);
25 carry := mod(n1(i),2);
26 end loop;
27 return ltrim(str,'0');
28 end;
29 begin
30 loop
31 l_last_dig := to_number(substr(l_num,-1,1));
32 l_res := to_char(mod(l_last_dig,2)) || l_res;
33 l_num := div2(l_num);
34 exit when l_num is null;
35 end loop;
36 return l_res;
37 end;
38 /
Function created.
SQL>
SQL> set serverout on
SQL> select dec_to_bit('12321231231098371928379182739182734589729384752345') bitstr from dual;
BITSTR
----------------------------------------------------------------------------------------------------------------------------------
1000011011100011011100011101111011000101010000000100000110010110101110100110110011011010000101111010101100100110010010001000110001
0000011010100110001110010011011001
Enjoy!
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