555

Do you mean the number 555 in math, or something else (area code, Roman numerals, etc.)?

If you want math facts about 555:

• Decimal factors: 555 = 3 × 5 × 37
• Not prime
• Divisible by: 3, 5, 15, and 37
• Sum of digits = 5+5+5 = 15; digital root = 6
• Harshad number in base 10 (555 ÷ 15 = 37)
• Number of positive divisors: 8 (1, 3, 5, 15, 37, 111, 185, 555)
• In other bases: hex 0x22B, octal 1053, binary 1000101011
• Roman numeral: DLV

If you want, I can tailor these to a specific exam topic (modular arithmetic, factorization, number bases, etc.) or give you quick practice problems. What would you like to focus on?