1640
1640 is the year Portugal regained independence from Spain.
- Even
- Composite
Where 1640 fits
Why 1640 is special
Sixty years of Spanish rule ended in a coup, and the war of restoration ran a further 28 years before Spain recognised it.
Factors & digit properties
- Divisors (16)
- 1, 2, 4, 5, 8, 10, 20, 40, 41, 82, 164, 205, 328, 410, 820, 1640
- Prime factorisation
- 2^3 × 5 × 41
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 1640
- Binary
- 11001101000
- Octal
- 3150
- Hexadecimal
- 668
- Roman numeral
- MDCXL
- Scientific notation
- 1.640 × 10^3
Other mathematical patterns
- Abundant number
Related numbers & connections
Portugal declared independence from Spain in 1640 and Spain recognised it in 1668 — a coup that took a day and a war that took twenty-eight years.
View 1668 →Other connections
- developed from1668
why?
Strength 0.50, confidence "high".
History
Portugal's 1640 restoration took a day to declare and 28 years to secure. Spain did not recognise Portuguese independence until 1668.
DocumentedHistoryGeography: Portugal and SpainPeriod: 1640–1668
Common questions
Is 1640 a prime number?
No, 1640 is not prime.
What are the factors of 1640?
The factors of 1640 are 1, 2, 4, 5, 8, 10, 20, 40, 41, 82, 164, 205, 328, 410, 820, 1640.
What is 1640 in Roman numerals?
1640 in Roman numerals is MDCXL.
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