However, if you're looking for something that sounds similar, you could try:
* "mitten" (the "tt" sounds like a "t" in "77")
* "written" (again, the "tt" sounds like a "t" in "77")
Or, you could get creative with homophones:
* "seven" (although it's not a perfect rhyme, it's thematically related to the number 77)
* "heaven" (again, a thematic connection rather than a true rhyme)
Let me know if you're looking for something else!