1420
1,420 MHz is the frequency of the hydrogen line, and the frequency SETI listens on.
- Even
- Composite
Where 1420 fits
Why 1420 is special
Hydrogen is the most abundant element in the universe and emits at this frequency, so any technological civilisation studying the sky would know it. That shared reference is the argument for listening there, and the same frequency is used to map the structure of our own galaxy.
Same number, different meanings
How 1420 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Hydrogen is the most abundant element in the universe and emits at this frequency, so any technological civilisation studying the sky would know it. That shared reference is the argument for listening there, and the same frequency is used to map the structure of our own galaxy.
- History
In 1420, the Treaty of Troyes made Henry V heir to the French throne (France).
- Science
Hydrogen is the most abundant element in the universe and emits at 1,420 MHz, so any civilisation studying the sky would find it. That shared reference is the argument for listening there for signals, and the same line is used to map the structure of our own galaxy.
1420 is part of
Factors & digit properties
- Divisors (12)
- 1, 2, 4, 5, 10, 20, 71, 142, 284, 355, 710, 1420
- Prime factorisation
- 2^2 × 5 × 71
- Digit sum
- 7
- Digital root
- 7
Representations
- Decimal
- 1420
- Scientific notation
- 1.420 × 10^3
Roman numerals
M C D X X
MCDXX uses the subtractive pair CD: a hundred before five hundred — five hundred minus a hundred.
Binary
1 0 1 1 0 0 0 1 1 0 0
1 × 1,024 + 0 × 512 + 1 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 1,420
Octal
2 6 1 4
2 × 512 + 6 × 64 + 1 × 8 + 4 × 1 = 1,420
Hexadecimal
5 8 c
5 × 256 + 8 × 16 + c × 1 = 1,420
Read as powers of two: 1,024 + 256 + 128 + 8 + 4 = 1,420.
In historical numeral systems
Egyptian
1 lotus, 4 coils of rope, 2 hobbles
1 × 1,000 + 4 × 100 + 2 × 10 = 1,420. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
2 corner wedges + 3 vertical wedges (sixties place), 4 corner wedges (units place)
23 × 60 + 40 = 1420. 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
1420 is a year in the 15th century, in the 1420s.
Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
History
In 1420, the Treaty of Troyes made Henry V heir to the French throne (France).
DocumentedHistoryGeography: FrancePeriod: 1420In 1420, the Forbidden City was completed at Beijing after fourteen years of work (China).
DocumentedHistoryGeography: ChinaPeriod: 1420
Science
Hydrogen is the most abundant element in the universe and emits at 1,420 MHz, so any civilisation studying the sky would find it. That shared reference is the argument for listening there for signals, and the same line is used to map the structure of our own galaxy.
DocumentedScience
Common questions
Is 1420 a prime number?
No, 1420 is not prime.
What are the factors of 1420?
The factors of 1420 are 1, 2, 4, 5, 10, 20, 71, 142, 284, 355, 710, 1420.
What is 1420 in Roman numerals?
1420 in Roman numerals is MCDXX. CD is subtractive: a hundred before five hundred — five hundred minus a hundred. Written additively it would be MCCCCXX, 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: 3 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026