Google has changed its birthdate multiple times
Google released a doodle to mark its 18th birthday on September 27, but the tech-giant notably admitted in 2013 that it was not sure about its actual birthdate. While Google has celebrated its birthday on September 27 since 2006, it had released doodles on September 7, 8, and 26 in earlier years. Interestingly, Google was incorporated on September 4, 1998.