2009
2009 is the year the Bitcoin network started.
- Odd
- Composite
Where 2009 fits
Why 2009 is special
The first block contains a headline from that day's Times about bank bailouts, which timestamps it and is widely read as commentary. Its creator's identity remains unknown, which is unusual for a system now holding substantial value.
Same number, different meanings
How 2009 is understood across different contexts — never implying one meaning because of another.
- Mathematics
The first block contains a headline from that day's Times about bank bailouts, which timestamps it and is widely read as commentary. Its creator's identity remains unknown, which is unusual for a system now holding substantial value.
- History
In 2009, Bitcoin's first block was mined, introducing a working blockchain currency.
- Technology & computing
Bitcoin's genesis block carries a Times headline from 3 January 2009 about a second bank bailout. It functions as a timestamp proving the block was not created earlier, and it is read as a statement of intent — the first is verifiable, the second is inference.
2009 is part of
Factors & digit properties
- Divisors (6)
- 1, 7, 41, 49, 287, 2009
- Prime factorisation
- 7^2 × 41
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 2009
- Scientific notation
- 2.009 × 10^3
Roman numerals
M M I X
MMIX uses the subtractive pair IX: one before ten — ten minus one.
Binary
1 1 1 1 1 0 1 1 0 0 1
1 × 1,024 + 1 × 512 + 1 × 256 + 1 × 128 + 1 × 64 + 0 × 32 + 1 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 2,009
Octal
3 7 3 1
3 × 512 + 7 × 64 + 3 × 8 + 1 × 1 = 2,009
Hexadecimal
7 d 9
7 × 256 + d × 16 + 9 × 1 = 2,009
Read as powers of two: 1,024 + 512 + 256 + 128 + 64 + 16 + 8 + 1 = 2,009.
In historical numeral systems
Egyptian
2 lotuses, 9 strokes
2 × 1,000 + 9 × 1 = 2,009. 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), 2 corner wedges + 9 vertical wedges (units place)
33 × 60 + 29 = 2009. 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
2009 is a year in the 21st century, in the 2000s.
Bitcoin nodes gossip over port 8333, and the network started in 2009 with a genesis block carrying a newspaper headline about bank bailouts.
View 8333 →History
In 2009, Bitcoin's first block was mined, introducing a working blockchain currency.
DocumentedHistoryGeography: globalPeriod: 2009
Technology & computing
Bitcoin's genesis block carries a Times headline from 3 January 2009 about a second bank bailout. It functions as a timestamp proving the block was not created earlier, and it is read as a statement of intent — the first is verifiable, the second is inference.
DocumentedTechnology & computingPeriod: 2009
Common questions
Is 2009 a prime number?
No, 2009 is not prime.
What are the factors of 2009?
The factors of 2009 are 1, 7, 41, 49, 287, 2009.
What is 2009 in Roman numerals?
2009 in Roman numerals is MMIX. IX is subtractive: one before ten — ten minus one. Written additively it would be MMVIIII, 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