Strobogrammatic

A kind of number

About Strobogrammatic

A strobogrammatic number reads the same when rotated 180°. Only digits 0, 1, 6, 8, 9 are used; 6 and 9 swap. For example, 69 → 96 (rotated) and 808 reads the same.

Key features

  • Valid digits: 0, 1, 6, 8, 9; 6 and 9 interchange when rotated.
  • Single-digit 0, 1, 8 are strobogrammatic; 69 and 96 form a pair.

Examples:

0, 1, 8, 69, 96, 101, 111, 808, 619, 916

Further reading