Related Clues:

• Telephone button without letters
• "__ size fits all"
• Countdown's penultimate number, perhaps
• Simple number
• White Monopoly item
• "___ Mo' Time"
• Mike-tester's word
• Loneliest number?
• Typical studio apartment room count
• Number of tiles per Scrabble set for the letter at the end of the answer to each starred clue
• Word before "... liftoff!"
• "The loneliest number," in a song
• Homophone for "won"
• What every number is divisible by
• It's its own square