555

Do you mean the number 555? Here are quick properties you can memorize or use in problems:

• Prime factorization: 555 = 3 × 5 × 37
• Divisibility: divisible by 3 (sum of digits 5+5+5=15), divisible by 5 (ends in 5); not divisible by 9, not divisible by 11
• Number of divisors: (1+1)(1+1)(1+1) = 8
• Euler’s totient: φ(555) = 288
• Roman numeral: DLV
• Binary/Octal/Hex:
  • Binary: 1000101011
  • Octal: 153 (0o153)
  • Hexadecimal: 0x22B

Possible quick practice problems:

• Find gcd(555, 840) → 15
• Find lcm(555, 840) → (555×840)/15 = 31080
• Verify φ(555) by using the prime factorization

If you meant something else (e.g., a specific exam problem or a different subject), tell me the context and I’ll tailor it.