Related Clues:

• Matchless, e.g.
• Unlike 666
• On an angle
• Like all but one prime
• Prompting a 'hmm,' perhaps
• Like all prime numbers except 2
• Like 1, 3, 5, 7 ...
• Really strange
• Like 9 or 5
• Not factual
• A math sign
• Like 1, 11, 111, and 1,111
• Incorrect
• Like an unpaired sock
• Abnormal