Monalisa is from the Bengali rendition of Mona Lisa — from the Italian Madonna Lisa (Lisa del Giocondo, c. Monalisa is one of the Bengali feminine names of the late 20th + 21st century — particularly popular as Bengali parents adopted the Italian Renaissance name.
Monalisa 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 Monalisa reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.