Bianca is the Italian word for "white" — used as a name to mean "fair" or "pure." It is the Italian equivalent of Blanche (French) and Blanca (Spanish). The same Indo-European root gives English "blank."
Bianca has been used in Italy for centuries and is popular across the Italian-speaking world. Today the name sits in the U.S.
Bianca 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 Bianca reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.