The Japanese are absolute gods at this.
They use mnemonic devices & puns like this to remember everything. One of my students used to remember her student number (7497) with the phrase "ナシ喰うな" (nashi kuu na), which means "DON'T EAT PEARS!"
And there's this famous poem:
"産医師異国に向かう/産後厄なく/産婦みやしろに/虫散々闇に鳴く"
"san ishi ikoku ni mukau / sango yaku naku / sanpu miyashiro ni / mushi sanzan yami ni naku"
Which means something nonsensical about an obstetrician going abroad, but if you just follow the sounds, it means 3.14159265 358979 3238462 643383279. Pi to 30 digits.
I had to rip it from Wikipedia, but I've heard plenty of students who have no interest in math rhyme this mnemonic off from memory when I asked them to (although most of them only make it to sanpu). It's damn impressive that a whole country of people can do this.
There's another mnemonic for root of 2, and another one for root of 3, and probably many many more.