1428
1428 is the year the Aztec Triple Alliance was formed.
- Even
- Composite
Where 1428 fits
Why 1428 is special
Three city-states allied and dominated central Mexico for ninety years. The empire Cortés encountered was less than a century old.
1428 is part of
Factors & digit properties
- Divisors (24)
- 1, 2, 3, 4, 6, 7, 12, 14, 17, 21, 28, 34, 42, 51, 68, 84, 102, 119, 204, 238, 357, 476, 714, 1428
- Prime factorisation
- 2^2 × 3 × 7 × 17
- Digit sum
- 15
- Digital root
- 6
Representations
- Decimal
- 1428
- Scientific notation
- 1.428 × 10^3
Roman numerals
M C D X X V I I I
MCDXXVIII uses the subtractive pair CD: a hundred before five hundred — five hundred minus a hundred.
Binary
1 0 1 1 0 0 1 0 1 0 0
1 × 1,024 + 0 × 512 + 1 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 0 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 1,428
Octal
2 6 2 4
2 × 512 + 6 × 64 + 2 × 8 + 4 × 1 = 1,428
Hexadecimal
5 9 4
5 × 256 + 9 × 16 + 4 × 1 = 1,428
Read as powers of two: 1,024 + 256 + 128 + 16 + 4 = 1,428.
In historical numeral systems
Egyptian
1 lotus, 4 coils of rope, 2 hobbles, 8 strokes
1 × 1,000 + 4 × 100 + 2 × 10 + 8 × 1 = 1,428. 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 + 8 vertical wedges (units place)
23 × 60 + 48 = 1428. 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
1428 is a year in the 15th century, in the 1420s.
The Aztec Triple Alliance formed in 1428 and Pizarro captured the Inca emperor in 1532. Both empires the Spanish encountered were recent, and both fell to disease as much as to conquest.
View 1532 →Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
Other connections
- is associated with1532
why?
Strength 0.50, confidence "high".
History
In 1428, the Triple Alliance of Tenochtitlan, Texcoco and Tlacopan formed the Aztec empire (Mesoamerica).
DocumentedHistoryGeography: MesoamericaPeriod: 1428The Aztec empire dates from a 1428 alliance of three city-states, so it was roughly ninety years old when the Spanish arrived. Its recent formation is part of why subject peoples allied against it.
DocumentedHistoryGeography: MexicoPeriod: 1428
Common questions
Is 1428 a prime number?
No, 1428 is not prime.
What are the factors of 1428?
The factors of 1428 are 1, 2, 3, 4, 6, 7, 12, 14, 17, 21, 28, 34, 42, 51, 68, 84, 102, 119, 204, 238, 357, 476, 714, 1428.
What is 1428 in Roman numerals?
1428 in Roman numerals is MCDXXVIII. CD is subtractive: a hundred before five hundred — five hundred minus a hundred. Written additively it would be MCCCCXXVIII, 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