Esti is from the Hungarian esti (evening) — also Yiddish diminutive of Esther. Esti Klein — modern Yiddish-American figure. Esti Yiddish word — appears throughout Yiddish theater, literature, and song including the works of Sholem Aleichem and Isaac Bashevis Singer (Nobel Literature 1978). Princess Esti — modern heritage naming.
Esti 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 Esti reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.