Complex sentence: The album is also titled "Four" or "4" in the USA; the numeral "4" is the title as shown on the cover in all countries, but a written-out title appears on the spine and label.
Split into simpler sentences: The album is also titled "Four" or "4" in the USA. The numeral "4" is the title as shown on the cover in all countries, but a written-out title appears on the spine and label.