555

Do you mean the number 555 or something like the 555 timer IC? If you mean the number, here are quick properties you can use for exam prep:

• Prime factorization: 555 = 3 × 5 × 37
• Divisors: 1, 3, 5, 15, 37, 111, 185, 555
• Divisible by: 3 and 5 (and hence by 15)
• Sum of digits: 5+5+5 = 15; digital root = 6
• Roman numeral: DLV
• Binary: 1000101011
• Hexadecimal: 0x22B
• Octal: 1053_8

Quick practice problems you can try:

• gcd(555, 270)
• lcm(555, 40)
• Convert 555 to base 7 or base 8 (we already have 1053_8)
• Express 555 in Roman numerals (DLV)

Would you like more problems, or should I explain the 555 timer IC if that’s what you had in mind?