The combination to Booth's gun safe is 447. The number 447 has appeared repeatedly throughout the series as an "easter egg" for fans in easy to miss ways (alarm clocks, door numbers, etc.). Series creator Hart Hanson has confirmed that the repetition of the number is intentional and meant to be hard to spot. In a Paley Center panel, he stated that the significance of the number will be revealed in the very last episode, and that even the actors don't know the meaning behind 447.
Booth枪支保险柜的密码是447。447在本剧就如同彩蛋一直不停地在不经意间出现。制片人Hart Hanson确认这个数字的出现是有意而为且故意做的很难发现。某次剧组见面会上,他说这个数字的意义会在最后一集揭晓,甚至演员都不知道447的意义。(之前曾出现于S4E26 S5E22 S6E22 S7E13 S9E01)