Almudena comes from the Arabic al-mudayna, meaning "the citadel." The title of the Virgin Mary as patron of Madrid — Nuestra Señora de la Almudena. The statue was hidden in the city walls during Moorish rule and rediscovered in 1085.
Almudena is widely used in Spain.
Almudena does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Almudena reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.