555

Not sure what you need with “555.” Here are a few common contexts—tell me which one (or something else) you want:

• Math: factorization, properties, or a quick problem involving 555 (e.g., prime factors: 3 × 5 × 37).
• Roman numerals: 555 = DLV.
• Electronics: the 555 timer IC (astable/monostable circuits).
• General trivia: 555 as a fictitious phone number in media.

Tell me the subject and what you’d like to do (explain, solve a problem, or practice).