Tatiana comes from the Latin Tatianus, the feminine of Tatianus, derived from Titus or possibly the Sabine king Titus Tatius.
Tatiana is among the most popular girl names in Russia and across Eastern Europe. Today it sits in the U.S. top 350.
Tatiana 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 Tatiana reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.