1928
1928 is the year penicillin was discovered.
- Even
- Composite
Where 1928 fits
Why 1928 is special
Fleming noticed mould killing bacteria on a contaminated plate and published, but could not produce the drug in useful quantity. It took Florey and Chain's work a decade later to make it a medicine, and all three shared the Nobel Prize.
1928 is part of
Factors & digit properties
- Divisors (8)
- 1, 2, 4, 8, 241, 482, 964, 1928
- Prime factorisation
- 2^3 × 241
- Digit sum
- 20
- Digital root
- 2
Representations
- Decimal
- 1928
- Scientific notation
- 1.928 × 10^3
Roman numerals
M C M X X V I I I
MCMXXVIII uses the subtractive pair CM: a hundred before a thousand — a thousand minus a hundred.
Binary
1 1 1 1 0 0 0 1 0 0 0
1 × 1,024 + 1 × 512 + 1 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 0 × 1 = 1,928
Octal
3 6 1 0
3 × 512 + 6 × 64 + 1 × 8 + 0 × 1 = 1,928
Hexadecimal
7 8 8
7 × 256 + 8 × 16 + 8 × 1 = 1,928
Read as powers of two: 1,024 + 512 + 256 + 128 + 8 = 1,928.
In historical numeral systems
Egyptian
1 lotus, 9 coils of rope, 2 hobbles, 8 strokes
1 × 1,000 + 9 × 100 + 2 × 10 + 8 × 1 = 1,928. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 2 vertical wedges (sixties place), 8 vertical wedges (units place)
32 × 60 + 8 = 1928. 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
1928 is a year in the 20th century, in the 1920s.
Lind ran a controlled trial in 1747 and the navy took forty years to act; Fleming observed penicillin in 1928 and it took a decade and different people to make it a medicine. Evidence and adoption are separate problems.
View 1747 →Science
In 1928, Alexander Fleming observed the antibacterial effect of penicillin (Britain).
DocumentedScienceGeography: BritainPeriod: 1928Fleming observed mould killing bacteria on a contaminated plate in 1928 and could not produce the substance in quantity. Florey and Chain's work a decade later turned it into a medicine, and all three shared the Nobel Prize.
DocumentedSciencePeriod: 1928
Common questions
Is 1928 a prime number?
No, 1928 is not prime.
What are the factors of 1928?
The factors of 1928 are 1, 2, 4, 8, 241, 482, 964, 1928.
What is 1928 in Roman numerals?
1928 in Roman numerals is MCMXXVIII. CM is subtractive: a hundred before a thousand — a thousand minus a hundred. Written additively it would be MDCCCCXXVIII, 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