1405
1405 is the year Zheng He's first treasure voyage sailed.
- Odd
- Composite
Where 1405 fits
Why 1405 is special
His fleets reached East Africa decades before Portuguese ships rounded the Cape, with ships far larger than anything Europe had. The voyages were then discontinued and the records largely destroyed.
Factors & digit properties
- Divisors (4)
- 1, 5, 281, 1405
- Prime factorisation
- 5 × 281
- Digit sum
- 10
- Digital root
- 1
Representations
- Decimal
- 1405
- Binary
- 10101111101
- Octal
- 2575
- Hexadecimal
- 57d
- Roman numeral
- MCDV
- Scientific notation
- 1.405 × 10^3
Other mathematical patterns
- Deficient number
- Semiprime
Related numbers & connections
Beijing became the capital in 1421 under the same emperor who sent Zheng He's treasure voyages from 1405. Both were assertions of Ming reach, and both were reversed by later policy.
View 1421 →Other connections
- is associated with1421
why?
Strength 0.50, confidence "high".
Geography
Zheng He's fleets reached East Africa from 1405 with ships several times the size of European vessels. The programme was ended by later Ming policy and much of its documentation destroyed, which is why its scale is reconstructed rather than simply known.
DocumentedGeographyGeography: China and the Indian OceanPeriod: 1405–1433
Common questions
Is 1405 a prime number?
No, 1405 is not prime.
What are the factors of 1405?
The factors of 1405 are 1, 5, 281, 1405.
What is 1405 in Roman numerals?
1405 in Roman numerals is MCDV.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 3 August 2026