Aum is from the Sanskrit Auṁ (ॐ) — the primordial sound + sacred syllable in Hindu + Buddhist + Jain + Sikh traditions.
Aum 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 Aum reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.