2011
2011 is the year of the Arab Spring and the Fukushima nuclear accident.
- Odd
- Prime
Where 2011 fits
Why 2011 is special
Protests spread across North Africa and the Middle East within weeks, with outcomes that diverged sharply by country. The same year, an earthquake and tsunami caused the Fukushima Daiichi accident, which changed nuclear policy well beyond Japan.
2011 is part of
Factors & digit properties
- Divisors (2)
- 1, 2011
- Prime factorisation
- 2011
- Digit sum
- 4
- Digital root
- 4
Representations
- Decimal
- 2011
- Scientific notation
- 2.011 × 10^3
Roman numerals
M M X I
Binary
1 1 1 1 1 0 1 1 0 1 1
1 × 1,024 + 1 × 512 + 1 × 256 + 1 × 128 + 1 × 64 + 0 × 32 + 1 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 2,011
Octal
3 7 3 3
3 × 512 + 7 × 64 + 3 × 8 + 3 × 1 = 2,011
Hexadecimal
7 d b
7 × 256 + d × 16 + b × 1 = 2,011
Read as powers of two: 1,024 + 512 + 256 + 128 + 64 + 16 + 8 + 2 + 1 = 2,011.
In historical numeral systems
Egyptian
2 lotuses, 1 hobble, 1 stroke
2 × 1,000 + 1 × 10 + 1 × 1 = 2,011. 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), 3 corner wedges + 1 vertical wedge (units place)
33 × 60 + 31 = 2011. 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
2011 is a year in the 21st century, in the 2010s.
Chernobyl and Fukushima, the two accidents rated at the top of the international nuclear event scale. One followed a flawed test on a flawed design, the other a tsunami exceeding what the site was built for.
View 1986 →History
In 2011, the Tōhoku earthquake and tsunami caused the Fukushima nuclear accident (Japan).
DocumentedHistoryGeography: JapanPeriod: 2011Protests spread across North Africa and the Middle East within weeks in 2011, with results that diverged sharply by country — from changes of government to prolonged civil war. The same year, an earthquake and tsunami caused the Fukushima Daiichi accident, which reshaped nuclear policy well beyond Japan.
DocumentedHistoryPeriod: 2011
Common questions
Is 2011 a prime number?
Yes, 2011 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 2011?
The factors of 2011 are 1, 2011.
What is 2011 in Roman numerals?
2011 in Roman numerals is MMXI.
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