1918
1918 is the year the First World War ended and the influenza pandemic reached its deadliest phase.
- Even
- Composite
Where 1918 fits
Why 1918 is special
1918 carried two catastrophes that are usually remembered separately. The armistice took effect at 11 a.m. on 11 November — the eleventh hour of the eleventh day of the eleventh month, a time chosen for symbolism, with men still dying that morning. The influenza pandemic of the same year killed more people worldwide than the war did.
Same number, different meanings
How 1918 is understood across different contexts — never implying one meaning because of another.
- Mathematics
1918 carried two catastrophes that are usually remembered separately. The armistice took effect at 11 a.m. on 11 November — the eleventh hour of the eleventh day of the eleventh month, a time chosen for symbolism, with men still dying that morning. The influenza pandemic of the same year killed more people worldwide than the war did.
- History
In 1918, the First World War ended and an influenza pandemic began that killed tens of millions.
- Technology & computing
RFC 1918 reserves 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 for private use, so the same addresses are in use on millions of networks simultaneously. That reuse is what stretched IPv4 far past the point its address space should have allowed.
1918 is part of
Factors & digit properties
- Divisors (8)
- 1, 2, 7, 14, 137, 274, 959, 1918
- Prime factorisation
- 2 × 7 × 137
- Digit sum
- 19
- Digital root
- 1
Representations
- Decimal
- 1918
- Scientific notation
- 1.918 × 10^3
Roman numerals
M C M X V I I I
MCMXVIII uses the subtractive pair CM: a hundred before a thousand — a thousand minus a hundred.
Binary
1 1 1 0 1 1 1 1 1 1 0
1 × 1,024 + 1 × 512 + 1 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 1 × 16 + 1 × 8 + 1 × 4 + 1 × 2 + 0 × 1 = 1,918
Octal
3 5 7 6
3 × 512 + 5 × 64 + 7 × 8 + 6 × 1 = 1,918
Hexadecimal
7 7 e
7 × 256 + 7 × 16 + e × 1 = 1,918
Read as powers of two: 1,024 + 512 + 256 + 64 + 32 + 16 + 8 + 4 + 2 = 1,918.
In historical numeral systems
Egyptian
1 lotus, 9 coils of rope, 1 hobble, 8 strokes
1 × 1,000 + 9 × 100 + 1 × 10 + 8 × 1 = 1,918. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 1 vertical wedge (sixties place), 5 corner wedges + 8 vertical wedges (units place)
31 × 60 + 58 = 1918. Places are separated by a space on the tablet, with the higher place written first.
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
Related numbers & connections
RFC 1918 is cited by number so routinely that '1918 addresses' is how engineers name private address space in conversation.
Haber demonstrated ammonia synthesis in 1909, feeding a large share of the world's population, and directed chemical weapons development during the war that ended in 1918.
View 1909 →Numbers Around Us
- appears inNumbers assigned as identifiers
why?
Strength 0.50, confidence "high".
- appears inHistorical years
why?
Strength 0.50, confidence "high".
- appears inNumbers that make the internet work
why?
Strength 0.50, confidence "high".
- appears alongside1945
why?
Strength 0.50, confidence "medium".
History
In 1918, the First World War ended and an influenza pandemic began that killed tens of millions.
DocumentedHistoryGeography: globalPeriod: 1918The armistice was signed at around 5 a.m. and made effective at 11 a.m. on 11 November, a delay chosen for its symmetry. Fighting continued through those six hours and men were killed in them, which is why the timing is remembered as much for its cost as for its neatness.
DocumentedHistoryPeriod: 11 November 1918
Technology & computing
RFC 1918 reserves 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 for private use, so the same addresses are in use on millions of networks simultaneously. That reuse is what stretched IPv4 far past the point its address space should have allowed.
DocumentedTechnology & computing
Common questions
Is 1918 a prime number?
No, 1918 is not prime.
What are the factors of 1918?
The factors of 1918 are 1, 2, 7, 14, 137, 274, 959, 1918.
What is 1918 in Roman numerals?
1918 in Roman numerals is MCMXVIII. CM is subtractive: a hundred before a thousand — a thousand minus a hundred. Written additively it would be MDCCCCXVIII, which Roman inscriptions used freely — the strict subtractive form is a later convention.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 3 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026