555

Do you mean the number 555, or something else (like the 555 timer IC, a page/problem, etc.)? I can help in several ways. Here are quick options:

Math facts about 555

• 555 = 3 × 5 × 37
• Divisors: 1, 3, 5, 15, 37, 111, 185, 555 (8 divisors)
• Sum of divisors = (1+3)(1+5)(1+37) = 4 × 6 × 38 = 912
• In Roman numerals: DLV
• Binary: 1000101011
• Hex: 0x22B
• It’s a repdigit in base 10 (three 5s)

Quick practice problems I can walk you through

• Is 555 prime? (Answer: no; factors as above)
• What is 555 in other bases (e.g., base 2, base 16—see above)?
• Find the number of divisors and the sum of all divisors (8 divisors, sum 912)

If you meant something else

• 555 timer IC: I can cover astable/monostable modes, formulas for frequency and duty cycle
• A problem where 555 appears (modular arithmetic, factoring, etc.)
• Anything else you’re studying for your exam

Tell me which option you want, or share a specific problem and I’ll work through it with you.