787
The Boeing 787 was the first airliner with a mostly composite airframe.
- Odd
- Prime
Where 787 fits
Why 787 is special
Carbon fibre rather than aluminium allows higher cabin pressure and humidity, which measurably reduces fatigue on long flights. Its lithium-ion batteries caused a fleet grounding in 2013, the first for an entire type in the United States since 1979.
Same number, different meanings
How 787 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Carbon fibre rather than aluminium allows higher cabin pressure and humidity, which measurably reduces fatigue on long flights. Its lithium-ion batteries caused a fleet grounding in 2013, the first for an entire type in the United States since 1979.
- Technology & computing
CWE-787 is an out-of-bounds write, the most consequential memory safety defect because it corrupts adjacent data rather than merely reading it. It has ranked first in the CWE Top 25 in several years.
- Sport
The Mazda 787B won the 1991 Le Mans 24 Hours, the only victory by a rotary-engined car and, for many years, the only win by a Japanese manufacturer. Rotary engines were excluded from the following season.
787 is part of
Factors & digit properties
- Divisors (2)
- 1, 787
- Prime factorisation
- 787
- Digit sum
- 22
- Digital root
- 4
Representations
- Decimal
- 787
- Scientific notation
- 7.870 × 10^2
Roman numerals
D C C L X X X V I I
Binary
1 1 0 0 0 1 0 0 1 1
1 × 512 + 1 × 256 + 0 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 787
Octal
1 4 2 3
1 × 512 + 4 × 64 + 2 × 8 + 3 × 1 = 787
Hexadecimal
3 1 3
3 × 256 + 1 × 16 + 3 × 1 = 787
Read as powers of two: 512 + 256 + 16 + 2 + 1 = 787.
In historical numeral systems
Egyptian
7 coils of rope, 8 hobbles, 7 strokes
7 × 100 + 8 × 10 + 7 × 1 = 787. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 corner wedge + 3 vertical wedges (sixties place), 7 vertical wedges (units place)
13 × 60 + 7 = 787. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
psi, then pi, then zeta, marked as a numeral
psi-pi-zeta + keraia
psi + pi + zeta written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
tav, then shin, then pe, then zayin
tav-shin-pe-zayin
tav (400) + shin (300) + pe (80) + zayin (7) = 787, written in descending order.
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
- Palindromic number
- Deficient number
- Lucky number (mathematical sieve)
Related numbers & connections
Out-of-bounds read and out-of-bounds write are the two halves of the same memory safety failure, and both sit near the top of the CWE Top 25 every year.
View 125 →The 777 was designed entirely on computer; the 787 went further and replaced most of the aluminium with carbon fibre, allowing higher cabin pressure and humidity.
View 777 →Technology & computing
CWE-787 is an out-of-bounds write, the most consequential memory safety defect because it corrupts adjacent data rather than merely reading it. It has ranked first in the CWE Top 25 in several years.
DocumentedTechnology & computingGeography: International — MITRE CWEPeriod: 2006–A mostly carbon-fibre airframe tolerates higher cabin pressure and humidity than aluminium, which measurably reduces fatigue on long flights. Its lithium-ion batteries caused the first US grounding of an entire aircraft type since 1979.
DocumentedTechnology & computing
Sport
The Mazda 787B won the 1991 Le Mans 24 Hours, the only victory by a rotary-engined car and, for many years, the only win by a Japanese manufacturer. Rotary engines were excluded from the following season.
DocumentedSportGeography: FrancePeriod: 1991
Common questions
Is 787 a prime number?
Yes, 787 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 787?
The factors of 787 are 1, 787.
What is 787 in Roman numerals?
787 in Roman numerals is DCCLXXXVII.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 3 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026