555

Do you want help with 555 as a number (math) or the 555 timer IC, or something else? Here are quick notes in case you’re prepping for math problems:

• Factorization: 555 = 3 × 5 × 37
• Divisibility: divisible by 3 and 5; not by 9 or 11
• Binary: 555 = 1000101011₂
• Hex: 555 = 0x22B
• Roman numeral: 555 = DLV
• Digit sum: 5 + 5 + 5 = 15 (digital root 6)

If you meant the 555 timer IC (electronics), I can give you the astable/monostable formulas and typical configurations. Which would you like to focus on?