Debug logs often embed numbers within text. To extract only the numbers:

SELECT TO_NUMBER(REGEXP_REPLACE('INV#8674767JSDEPOSIT PO12345678', '\\D', '')) AS out_put
FROM dual;

SELECT TO_NUMBER(REGEXP_REPLACE('INV#8674767JSDEPOSIT PO12345678', '[^0-9]+', '')) AS out_put
FROM dual;

Both return 867476712345678, effectively isolating digits from alphanumeric strings.