If you have a prescription bottle that says "hydrocodone 500 mg" it must be mislabeled. In the U.S., hydrocodone always comes combined with either acetaminophin or ibuprofen – usually acetaminophen. Acetaminophen is often labeled as apap. There should be two numbers with any hydrocodone prescription (like the second one you mentioned). In that case, hydrocodone-apap 5-325 means there is 5 mg of hydrocodone and 325 mg of acetaminophen. Hydrocodone is available in 5 mg, 7.5 mg, and 10 mg dosages combined with various strengths of acetaminophen.
Double check the prescription labeled "hydrocodone 500 mg" to make sure you read it correctly. If so, take it back to the pharmacy and ask them to tell you what the actual dosage is and re-label it.