555

Do you want something about the number 555, or something else (like the 555 timer IC)? Here are quick math facts just in case:

• Decimal: 555
• Prime factorization: 3 × 5 × 37
• Divisible by: 3, 5, and 15 (555 = 15 × 37); not by 9 or 25
• Sum of digits: 5+5+5 = 15 → a Harshad (Niven) number since 555 ÷ 15 = 37
• Roman numeral: DLV
• Binary: 1000101011₂
• Hexadecimal: 0x22B
• 555 = 15 × 37

If you meant the 555 timer IC, I can explain its operation and the astable frequency formula: f ≈ 1.44 / ((RA + 2RB) C). Tell me which you need.