“123456” is the lead single from Fitz and the Tantrums' fourth studio album, All The Feels. It has a fun, mainstream pop sound compared to much of their previous material. It was released as the album’s lead single on March 20th, 2019.

Singer and songwriter Michael Fitzpatrick stated that the song was an “emotional song” and the “turning point of the record” for him, “capturing the moment when optimism, hope and confidence were found after a dark period as an artist trying to write for this album”.