555

What would you like to do with 555? Here are a few quick math facts, in case that’s what you need for an exam:

• Prime factorization: 555 = 3 × 5 × 37
• Divisors: 1, 3, 5, 15, 37, 111, 185, 555
• Euler’s totient: φ(555) = 288
• Sum of divisors: σ(555) = 912
• Hexadecimal: 0x22B
• Binary: 1000101011
• Roman numeral: DLV

If you want, I can turn this into a practice problem (e.g., find gcd(555, n), or compute something modulo 555), or we can cover another topic (Roman numerals, base conversions, or electronics 555 timer). Which would you prefer?