1840
1840 is the year the Penny Black created modern postage.
- Even
- Composite
Where 1840 fits
Why 1840 is special
Prepayment by the sender, at one price regardless of distance, replaced a system where the recipient paid according to how far the letter had come. Every postal system in the world adopted the model within decades.
Same number, different meanings
How 1840 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Prepayment by the sender, at one price regardless of distance, replaced a system where the recipient paid according to how far the letter had come. Every postal system in the world adopted the model within decades.
- History
In 1840, the Penny Black, the first adhesive postage stamp, was issued (Britain).
- Everyday life
The Penny Black established prepayment by the sender at a single price regardless of distance, replacing a system where the recipient paid by the mile. Every postal system in the world adopted the model within a few decades.
1840 is part of
Factors & digit properties
- Divisors (20)
- 1, 2, 4, 5, 8, 10, 16, 20, 23, 40, 46, 80, 92, 115, 184, 230, 368, 460, 920, 1840
- Prime factorisation
- 2^4 × 5 × 23
- Digit sum
- 13
- Digital root
- 4
Representations
- Decimal
- 1840
- Scientific notation
- 1.840 × 10^3
Roman numerals
M D C C C X L
MDCCCXL uses the subtractive pair XL: ten before fifty — fifty minus ten.
Binary
1 1 1 0 0 1 1 0 0 0 0
1 × 1,024 + 1 × 512 + 1 × 256 + 0 × 128 + 0 × 64 + 1 × 32 + 1 × 16 + 0 × 8 + 0 × 4 + 0 × 2 + 0 × 1 = 1,840
Octal
3 4 6 0
3 × 512 + 4 × 64 + 6 × 8 + 0 × 1 = 1,840
Hexadecimal
7 3 0
7 × 256 + 3 × 16 + 0 × 1 = 1,840
Read as powers of two: 1,024 + 512 + 256 + 32 + 16 = 1,840.
In historical numeral systems
Egyptian
1 lotus, 8 coils of rope, 4 hobbles
1 × 1,000 + 8 × 100 + 4 × 10 = 1,840. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges (sixties place), 4 corner wedges (units place)
30 × 60 + 40 = 1840. 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
Related numbers & connections
1840 is a year in the 19th century, in the 1840s.
Mail coaches from 1784 made letter delivery predictable, and the Penny Black in 1840 made it cheap and prepaid. Reliability came first and affordability second.
View 1784 →Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
Other connections
- developed from1784
why?
Strength 0.50, confidence "high".
History
In 1840, the Penny Black, the first adhesive postage stamp, was issued (Britain).
DocumentedHistoryGeography: BritainPeriod: 1840
Everyday life
The Penny Black established prepayment by the sender at a single price regardless of distance, replacing a system where the recipient paid by the mile. Every postal system in the world adopted the model within a few decades.
DocumentedEveryday lifeGeography: United KingdomPeriod: 1840
Common questions
Is 1840 a prime number?
No, 1840 is not prime.
What are the factors of 1840?
The factors of 1840 are 1, 2, 4, 5, 8, 10, 16, 20, 23, 40, 46, 80, 92, 115, 184, 230, 368, 460, 920, 1840.
What is 1840 in Roman numerals?
1840 in Roman numerals is MDCCCXL. XL is subtractive: ten before fifty — fifty minus ten. Written additively it would be MDCCCXXXX, 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