1985
1985 is the year the ozone hole was reported and DNA fingerprinting was invented.
- Odd
- Composite
Where 1985 fits
Why 1985 is special
British Antarctic Survey scientists published ozone measurements so low that satellite software had been discarding them as errors. Alec Jeffreys developed genetic fingerprinting the same year, and it was first used to clear an innocent suspect rather than convict a guilty one.
1985 is part of
Factors & digit properties
- Divisors (4)
- 1, 5, 397, 1985
- Prime factorisation
- 5 × 397
- Digit sum
- 23
- Digital root
- 5
Representations
- Decimal
- 1985
- Scientific notation
- 1.985 × 10^3
Roman numerals
M C M L X X X V
MCMLXXXV 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 0 1
1 × 1,024 + 1 × 512 + 1 × 256 + 1 × 128 + 1 × 64 + 0 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 1,985
Octal
3 7 0 1
3 × 512 + 7 × 64 + 0 × 8 + 1 × 1 = 1,985
Hexadecimal
7 c 1
7 × 256 + c × 16 + 1 × 1 = 1,985
Read as powers of two: 1,024 + 512 + 256 + 128 + 64 + 1 = 1,985.
In historical numeral systems
Egyptian
1 lotus, 9 coils of rope, 8 hobbles, 5 strokes
1 × 1,000 + 9 × 100 + 8 × 10 + 5 × 1 = 1,985. 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), 5 vertical wedges (units place)
33 × 60 + 5 = 1985. 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
- Semiprime
Related numbers & connections
1985 is a year in the 20th century, in the 1980s.
The ozone hole was reported in 1985 and the Montreal Protocol signed in 1987 — two years from measurement to a treaty every state has ratified.
View 1987 →Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
Other connections
- developed from1987
why?
Strength 0.50, confidence "high".
Science
In 1985, the Antarctic ozone hole was identified by the British Antarctic Survey.
DocumentedScienceGeography: globalPeriod: 1985British Antarctic Survey scientists reported ozone levels so low that satellite processing had been treating them as errors and throwing them away. DNA fingerprinting was invented the same year and first used to clear an innocent suspect rather than to convict.
DocumentedSciencePeriod: 1985
Common questions
Is 1985 a prime number?
No, 1985 is not prime.
What are the factors of 1985?
The factors of 1985 are 1, 5, 397, 1985.
What is 1985 in Roman numerals?
1985 in Roman numerals is MCMLXXXV. CM is subtractive: a hundred before a thousand — a thousand minus a hundred. Written additively it would be MDCCCCLXXXV, 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