Malalai is the name of the legendary Afghan heroine Malalai of Maiwand (c. The name means "sorrowful one" in Pashto.
Malala Yousafzai (born 1997), the Pakistani education activist and Nobel Peace Prize laureate, was named for Malalai of Maiwand.
Malalai 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 Malalai reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.