555

What would you like to do with the number 555? Here are a few quick options. Tell me which you want or ask something else:

• Factorization and divisors: 555 = 3 × 5 × 37. Divisors: 1, 3, 5, 15, 37, 111, 185, 555.
• Quick number theory notes: 555 is a Harshad number (divisible by the sum of its digits, 5+5+5=15; 555/15 = 37). It’s a repdigit (three identical digits).
• Roman numeral: 555 = DLV.
• Binary and other bases: 555 in binary is 1000101011. If you want, I can convert to base 3, base 7, base 16, etc.
• 555 timer: basic overview of the IC and common configurations (astable, monostable, bistable).
• Any other exam-related angle (word problem, sequence, modular arithmetic, etc.)—19

Tell me which direction you’d like, and I’ll dive in.