Sudan is 2.5 times larger than Zambia.
Area: 1,861,484 km2 World Factbook
Population: 35,482,233 (July 2014) World Factbook
Sudan, officially the Republic of the Sudan, is an Arab republic in the Nile Valley of North Africa, bordered by Egypt to the north, the Red Sea, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the southwest, Chad to the west and Libya to the northwest. Wikipedia
Area: 752,618 km2 World Factbook
Population: 14,638,505 (July 2014) World Factbook
The Republic of Zambia is a landlocked country in Southern Africa, neighboring the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west. Wikipedia