555

Not sure what you want about 555. Do you want math facts about the number, or something else (like the 555 timer IC, or practice problems)? Here are quick math facts to get you started:

• 555 = 3 × 5 × 37
• Sum of digits = 5 + 5 + 5 = 15
• Harshad (Niven) number: 555 ÷ 15 = 37
• Palindrome in base 10
• Roman numeral: DLV
• Binary: 1000101011
• Hexadecimal: 0x22B
• 555 mod 7 = 2 (since 7 × 79 = 553)

Would you like:

• a few exam-style practice questions (divisibility, factorization, base conversions) using 555, with solutions?
• an explanation of any of the above facts (e.g., Harshad numbers, base conversions)?
• information about the 555 timer IC and common applications?