311
311 is the telephone number for non-emergency municipal services in much of the United States and Canada.
- Odd
- Prime
Where 311 fits
Why 311 is special
Introduced in Baltimore in 1996 for a specific purpose: too many people were calling 911 about potholes and noise complaints, and the emergency line was the only number anyone knew. Splitting the traffic made both services work better, and the pattern was copied across North America.
311 is part of
Factors & digit properties
- Divisors (2)
- 1, 311
- Prime factorisation
- 311
- Digit sum
- 5
- Digital root
- 5
Representations
- Decimal
- 311
- Scientific notation
- 3.110 × 10^2
Roman numerals
C C C X I
Binary
1 0 0 1 1 0 1 1 1
1 × 256 + 0 × 128 + 0 × 64 + 1 × 32 + 1 × 16 + 0 × 8 + 1 × 4 + 1 × 2 + 1 × 1 = 311
Octal
4 6 7
4 × 64 + 6 × 8 + 7 × 1 = 311
Hexadecimal
1 3 7
1 × 256 + 3 × 16 + 7 × 1 = 311
Read as powers of two: 256 + 32 + 16 + 4 + 2 + 1 = 311.
In historical numeral systems
Egyptian
3 coils of rope, 1 hobble, 1 stroke
3 × 100 + 1 × 10 + 1 × 1 = 311. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
5 vertical wedges (sixties place), 1 corner wedge + 1 vertical wedge (units place)
5 × 60 + 11 = 311. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
tau, then iota, then alpha, marked as a numeral
tau-iota-alpha + keraia
tau + iota + alpha written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
shin, then yod, then alef
shin-yod-alef
shin (300) + yod (10) + alef (1) = 311, written in descending order.
Maya
3 bars (upper, twenties place) over 2 bars + 1 dot (lower, units place)
15 × 20 + 11 = 311. Places stack vertically with the smallest at the bottom, so the upper group is worth twenty times the lower.
Systems that simply cannot reach this value are left out. Where a script needs a font most readers do not have, the reading is given instead of the glyphs — see number systems for each system in full.
Other mathematical patterns
- Deficient number
- Twin prime
Related numbers & connections
311 appears in Numbers in law and public systems, the topic covering numbers that carry a documented law or public-systems fact.
Numbers Around Us
- appears inLaw and public systems
why?
Strength 0.50, confidence "high".
Law & regulation
The telephone number for non-emergency municipal services is 311 (much of the United States and Canada). Introduced to take non-urgent calls off 911. Its usefulness is measured the same way: a city that answers 311 well has fewer people calling the emergency number for a fallen tree.
DocumentedLaw & regulationGeography: much of the United States and Canada
Common questions
Is 311 a prime number?
Yes, 311 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 311?
The factors of 311 are 1, 311.
What is 311 in Roman numerals?
311 in Roman numerals is CCCXI.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 15 July 2026