Milcah (מִלְכָּה) is the Hebrew word for "queen" — from melech (king).
Milcah is widely used in religious Jewish and Christian families.
Milcah 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 Milcah reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.