555

Did you mean something specific about the number 555? Here are a few quick notes and a mini practice set you can use for exam prep. If you meant something else, tell me and I’ll tailor it.

Quick facts about 555

• Prime factorization: 3 × 5 × 37
• Divisors: 1, 3, 5, 15, 37, 111, 185, 555 (8 divisors)
• Roman numeral: DLV
• Digital root: 6 (5+5+5 = 15, 1+5 = 6)
• 555 = 5 × 111 = 5 × (3 × 37)

Mini practice (5 problems)

1. List all positive divisors of 555. (Answer: 1, 3, 5, 15, 37, 111, 185, 555)
2. Is 555 divisible by 9? By 3? By 5? (Answers: divisible by 3 and 5, but not by 9)
3. Compute 555 mod 7, 555 mod 11, and 555 mod 8. (Answers: mod 7 = 2; mod 11 = 5; mod 8 = 3)
4. Verify: 555 ÷ 15 = ? (Answer: 37)
5. What is 555^2? (Answer: 308,025)

If you want, I can generate a more focused set (number theory, algebra, calculus, etc.) or turn these into timed practice. What topic should we focus on next?