From The Simplest Bitcoin Book by Keysa - Simplest Bitcoin Edu
A mnemonic on #Bitcoin mechanics - level39's Satoshi #numbers (369 Clock)

- Bitcoin is designed to mine 6 blocks per hour (one block on average every 10 mins)

24 hrs .. 2+4=6
144 blocks/day .. 1+4+4=9
52560 blocks/year .. 5+2+5+6+0=18 .. 1+8=9
52704 blocks per leap year .. 5+2+7+0+4=18 .. 1+8=9
21 Million coins .. 2+1+0+0+0+0+0+0=3
33 Halvings .. 3+3=6
Difficulty adjusts every 2016 blocks .. 2+0+1+6=9
Block reward halving every 210000th block ( four years) .. 2+1+0+0+0+0=3

#simple #math