2500
2,500 million years ago marks the end of the Archean and the start of the Proterozoic.
Where 2500 fits
Why 2500 is special
The boundary is close to the Great Oxidation Event, when photosynthesising bacteria filled the atmosphere with oxygen and caused what was probably the largest extinction in Earth's history — of organisms for which oxygen was poison.
2500 is part of
Factors & digit properties
- Divisors (15)
- 1, 2, 4, 5, 10, 20, 25, 50, 100, 125, 250, 500, 625, 1250, 2500
- Prime factorisation
- 2^2 × 5^4
- Digit sum
- 7
- Digital root
- 7
Representations
- Decimal
- 2500
- Scientific notation
- 2.500 × 10^3
Roman numerals
M M D
Binary
1 0 0 1 1 1 0 0 0 1 0 0
1 × 2,048 + 0 × 1,024 + 0 × 512 + 1 × 256 + 1 × 128 + 1 × 64 + 0 × 32 + 0 × 16 + 0 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 2,500
Octal
4 7 0 4
4 × 512 + 7 × 64 + 0 × 8 + 4 × 1 = 2,500
Hexadecimal
9 c 4
9 × 256 + c × 16 + 4 × 1 = 2,500
Read as powers of two: 2,048 + 256 + 128 + 64 + 4 = 2,500.
In historical numeral systems
Egyptian
2 lotuses, 5 coils of rope
2 × 1,000 + 5 × 100 = 2,500. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
4 corner wedges + 1 vertical wedge (sixties place), 4 corner wedges (units place)
41 × 60 + 40 = 2500. 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
- Abundant number
- Powerful number
Related numbers & connections
The Archean-Proterozoic boundary around 2,500 million years ago and the start of the Ordovician at 485 both precede events that killed most life then existing.
View 485 →Other connections
- is associated with485
why?
Strength 0.50, confidence "high".
Science
Around 2,500 million years ago cyanobacteria oxygenated the atmosphere, which was catastrophic for the anaerobic life that dominated until then. It is plausibly the largest extinction event ever, caused by life itself.
DocumentedSciencePeriod: 2500 million years ago
Common questions
Is 2500 a prime number?
No, 2500 is not prime.
What are the factors of 2500?
The factors of 2500 are 1, 2, 4, 5, 10, 20, 25, 50, 100, 125, 250, 500, 625, 1250, 2500.
What is 2500 in Roman numerals?
2500 in Roman numerals is MMD.
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