Area code 021

021 is:

• in Iran, the telephone area code for the city of Tehran. This code became popularized by Tehrani rapper Hich Kas.
• in Ireland, the area code for the city of Cork and a surrounding part of County Cork.
• in Indonesia, the area code for the city of Jakarta.
• in New Zealand, the "area code" for cellular phones on the Vodafone network.
• in Pakistan, the area code for the city of Karachi.
• in Serbia, the area code for the city of Novi Sad.
• in South Africa, the area code for the city of Cape Town.
• in the United Kingdom, the former area code for Birmingham England (changed to 0121 on 16 April 1995).