11 - Repeating Prime
A two-digit repunit prime with many divisibility tricks.
Why this number matters
11 is a good puzzle-style number that helps people see patterns without needing advanced math.
Background / history
11 appears in recreational math traditions where simple steps produce surprising outcomes.
Simple example
A quick way to sanity-check 11: 3 + 8 = 11. You can also test divisibility (for example, 11 is not divisible by 2).
Key Facts
- 11 is frequently cited in curious numbers contexts.
Fun fact
11 is a prime number.