Lampetia (Λαμπετίη) is from the Greek lampō (to shine). One of the Heliades, daughters of Helios the Sun — with her sister Phaethusa, she kept Helios's sacred cattle on the island of Thrinacia. When Odysseus's crew slaughtered the cattle, she reported the crime to her father, who demanded their destruction.
Featured in Homer's Odyssey Book 12.
Lampetia 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 Lampetia reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.