1604
Kepler's supernova of 1604 is the last one seen in our galaxy with the naked eye.
- Even
- Composite
Where 1604 fits
Why 1604 is special
Four centuries have passed without another, though the expected rate is roughly one or two per century. Modern surveys find supernovae in other galaxies weekly, which makes the absence in our own a matter of luck and dust rather than of rarity.
Same number, different meanings
How 1604 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Four centuries have passed without another, though the expected rate is roughly one or two per century. Modern surveys find supernovae in other galaxies weekly, which makes the absence in our own a matter of luck and dust rather than of rarity.
- History
In 1604, Robert Cawdrey's Table Alphabeticall appeared, the first monolingual English dictionary (England).
- Science
The last naked-eye supernova in the Milky Way was seen in 1604, and the expected rate is one or two a century. The gap is attributed to dust obscuring the galactic plane rather than to supernovae having stopped, but it remains unexplained in any satisfying way.
1604 is part of
Factors & digit properties
- Divisors (6)
- 1, 2, 4, 401, 802, 1604
- Prime factorisation
- 2^2 × 401
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 1604
- Scientific notation
- 1.604 × 10^3
Roman numerals
M D C I V
MDCIV uses the subtractive pair IV: one before five — five minus one.
Binary
1 1 0 0 1 0 0 0 1 0 0
1 × 1,024 + 1 × 512 + 0 × 256 + 0 × 128 + 1 × 64 + 0 × 32 + 0 × 16 + 0 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 1,604
Octal
3 1 0 4
3 × 512 + 1 × 64 + 0 × 8 + 4 × 1 = 1,604
Hexadecimal
6 4 4
6 × 256 + 4 × 16 + 4 × 1 = 1,604
Read as powers of two: 1,024 + 512 + 64 + 4 = 1,604.
In historical numeral systems
Egyptian
1 lotus, 6 coils of rope, 4 strokes
1 × 1,000 + 6 × 100 + 4 × 1 = 1,604. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
2 corner wedges + 6 vertical wedges (sixties place), 4 corner wedges + 4 vertical wedges (units place)
26 × 60 + 44 = 1604. 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
1604 is a year in the 17th century, in the 1600s.
Kepler's supernova in 1604 and Galileo's telescope observations in 1610. Between them they removed the idea that the heavens were unchanging and that everything orbited the Earth.
View 1610 →History
In 1604, Robert Cawdrey's Table Alphabeticall appeared, the first monolingual English dictionary (England).
DocumentedHistoryGeography: EnglandPeriod: 1604
Science
The last naked-eye supernova in the Milky Way was seen in 1604, and the expected rate is one or two a century. The gap is attributed to dust obscuring the galactic plane rather than to supernovae having stopped, but it remains unexplained in any satisfying way.
DocumentedSciencePeriod: 1604
Common questions
Is 1604 a prime number?
No, 1604 is not prime.
What are the factors of 1604?
The factors of 1604 are 1, 2, 4, 401, 802, 1604.
What is 1604 in Roman numerals?
1604 in Roman numerals is MDCIV. IV is subtractive: one before five — five minus one. Written additively it would be MDCIIII, 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