Emmy is a German diminutive of Emma. Amalie Emmy Noether (1882-1935) is widely regarded as the most important woman in the history of mathematics — and one of the greatest mathematicians of the 20th century regardless of gender.
Emmy 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 Emmy reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.