56
Fifty-six delegates signed the United States Declaration of Independence, most of them not on 4 July. 56 is also the atomic number of barium, the element swallowed before certain X-rays because it blocks them.
- Even
- Composite
Where 56 fits
Why 56 is special
56 (2³ × 7) is a quieter number, most notable for the good company it keeps between two highly divisible neighbours.
56 connects to:
- 28 — has factor
Same number, different meanings
How 56 is understood across different contexts — never implying one meaning because of another.
- Mathematics
56 (2³ × 7) is a quieter number, most notable for the good company it keeps between two highly divisible neighbours.
- History
Fifty-six delegates signed the United States Declaration of Independence. Most did not sign on 4 July 1776: the engrossed copy was signed principally on 2 August, and several delegates added their names later still, which is why the signing and the date the document is celebrated on are two different things.
- Everyday life
Soluble barium compounds are poisonous, yet element 56 is swallowed deliberately in hospitals every day. Barium sulfate is so insoluble that it passes through the gut without being absorbed, while its heavy nucleus blocks X-rays — so it coats the digestive tract and makes soft tissue visible on a radiograph that would otherwise show almost nothing. The distinction between a barium salt and barium sulfate is the whole of the safety argument.
- Science
56 is the atomic number of barium. A barium sulfate suspension — the 'barium meal' — is swallowed before certain X-rays because barium blocks the rays, making otherwise invisible soft tissue show up clearly.
Factors & digit properties
- Divisors (8)
- 1, 2, 4, 7, 8, 14, 28, 56
- Prime factorisation
- 2^3 × 7
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 56
- Scientific notation
- 5.600 × 10^1
Roman numerals
L V I
Binary
1 1 1 0 0 0
1 × 32 + 1 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 0 × 1 = 56
Octal
7 0
7 × 8 + 0 × 1 = 56
Hexadecimal
3 8
3 × 16 + 8 × 1 = 56
Read as powers of two: 32 + 16 + 8 = 56.
In historical numeral systems
Egyptian
5 hobbles, 6 strokes
5 × 10 + 6 × 1 = 56. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
5 corner wedges + 6 vertical wedges
56 fits in a single sexagesimal place: 5 corner wedges + 6 vertical wedges.
Greek (Ionic)
nu, then stigma, marked as a numeral
nu-stigma + keraia
nu + stigma written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
nun, then vav
nun-vav
nun (50) + vav (6) = 56, written in descending order.
Chinese numerals
wǔ shí liù
wǔ shí liù
五 before 十 multiplies it: 5 tens. 六 after it adds 6. The written form mirrors the arithmetic — "wǔ shí liù". The financial (anti-fraud) form is 伍拾陸.
Maya
2 dots (upper, twenties place) over 3 bars + 1 dot (lower, units place)
2 × 20 + 16 = 56. Places stack vertically with the smallest at the bottom, so the upper group is worth twenty times the lower.
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
Related numbers & connections
28 is a factor of 56 (28 × 2 = 56).
View 28 →Mathematically related
- has factor28
why?
Strength 0.50, confidence "high".
History
Fifty-six delegates signed the United States Declaration of Independence. Most did not sign on 4 July 1776: the engrossed copy was signed principally on 2 August, and several delegates added their names later still, which is why the signing and the date the document is celebrated on are two different things.
DocumentedHistoryGeography: United StatesPeriod: 1776
Everyday life
Soluble barium compounds are poisonous, yet element 56 is swallowed deliberately in hospitals every day. Barium sulfate is so insoluble that it passes through the gut without being absorbed, while its heavy nucleus blocks X-rays — so it coats the digestive tract and makes soft tissue visible on a radiograph that would otherwise show almost nothing. The distinction between a barium salt and barium sulfate is the whole of the safety argument.
DocumentedEveryday life
Science
56 is the atomic number of barium. A barium sulfate suspension — the 'barium meal' — is swallowed before certain X-rays because barium blocks the rays, making otherwise invisible soft tissue show up clearly.
DocumentedScience
Mathematics
56 factors as 2³ × 7, sitting between the highly composite numbers 48 and 60.
DocumentedMathematics
Common questions
Why do you drink barium before an X-ray?
Because soft tissue is nearly invisible to X-rays and barium is not. Barium sulfate coats the digestive tract and blocks the rays, so the outline shows up. Soluble barium salts are poisonous, but barium sulfate is so insoluble that it passes straight through without being absorbed — the whole safety argument rests on that distinction.
Is 56 a prime number?
No, 56 is not prime.
What are the factors of 56?
The factors of 56 are 1, 2, 4, 7, 8, 14, 28, 56.
What is 56 in Roman numerals?
56 in Roman numerals is LVI.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 4 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026