1987
1987 is the year the Montreal Protocol was signed.
- Odd
- Prime
Where 1987 fits
Why 1987 is special
It phased out ozone-depleting chemicals and is the only UN treaty ratified by every member state. The ozone hole is measurably recovering, which makes it the clearest example of an international environmental agreement working.
Same number, different meanings
How 1987 is understood across different contexts — never implying one meaning because of another.
- Mathematics
It phased out ozone-depleting chemicals and is the only UN treaty ratified by every member state. The ozone hole is measurably recovering, which makes it the clearest example of an international environmental agreement working.
- History
In 1987, the Montreal Protocol was agreed to phase out ozone-depleting substances, and is often cited as the most successful environmental treaty.
- Law & regulation
The Montreal Protocol phased out ozone-depleting chemicals and is the only UN treaty ratified by every member state. The ozone hole is measurably recovering, which makes it the clearest evidence that international environmental agreements can work.
1987 is part of
Factors & digit properties
- Divisors (2)
- 1, 1987
- Prime factorisation
- 1987
- Digit sum
- 25
- Digital root
- 7
Representations
- Decimal
- 1987
- Scientific notation
- 1.987 × 10^3
Roman numerals
M C M L X X X V I I
MCMLXXXVII uses the subtractive pair CM: a hundred before a thousand — a thousand minus a hundred.
Binary
1 1 1 1 1 0 0 0 0 1 1
1 × 1,024 + 1 × 512 + 1 × 256 + 1 × 128 + 1 × 64 + 0 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 1,987
Octal
3 7 0 3
3 × 512 + 7 × 64 + 0 × 8 + 3 × 1 = 1,987
Hexadecimal
7 c 3
7 × 256 + c × 16 + 3 × 1 = 1,987
Read as powers of two: 1,024 + 512 + 256 + 128 + 64 + 2 + 1 = 1,987.
In historical numeral systems
Egyptian
1 lotus, 9 coils of rope, 8 hobbles, 7 strokes
1 × 1,000 + 9 × 100 + 8 × 10 + 7 × 1 = 1,987. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 3 vertical wedges (sixties place), 7 vertical wedges (units place)
33 × 60 + 7 = 1987. 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
- Lucky number (mathematical sieve)
Related numbers & connections
1987 is a year in the 20th century, in the 1980s.
The Montreal Protocol bound every state to phase out specific chemicals; the Paris Agreement lets each set its own targets with no enforcement. The first worked measurably and the second achieved universal participation.
View 2015 →History
In 1987, the Montreal Protocol was agreed to phase out ozone-depleting substances, and is often cited as the most successful environmental treaty.
DocumentedHistoryGeography: globalPeriod: 1987
Law & regulation
The Montreal Protocol phased out ozone-depleting chemicals and is the only UN treaty ratified by every member state. The ozone hole is measurably recovering, which makes it the clearest evidence that international environmental agreements can work.
DocumentedLaw & regulationGeography: International — every UN member statePeriod: 1987
Common questions
Is 1987 a prime number?
Yes, 1987 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 1987?
The factors of 1987 are 1, 1987.
What is 1987 in Roman numerals?
1987 in Roman numerals is MCMLXXXVII. CM is subtractive: a hundred before a thousand — a thousand minus a hundred. Written additively it would be MDCCCCLXXXVII, 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: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026