Yoohyeon is from the Korean yoo (유 — abundant, prosperous) + hyeon (현 — virtuous, wise). Kim Yoo-hyeon (Yoohyeon, 김유현, born 1997) is a Korean K-pop singer-songwriter — main vocalist + lead dancer of the K-pop girl group Dreamcatcher (드림캐쳐, Dreamcatcher Company, debuted January 2017).
Yoohyeon 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 Yoohyeon reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.