1661
1661 is the year the first European banknotes were issued.
- Odd
- Composite
Where 1661 fits
Why 1661 is special
Stockholms Banco issued notes to replace copper plate money so heavy it required a cart. The bank over-issued and collapsed within decades, which is also the first lesson in paper currency.
1661 is part of
Factors & digit properties
- Divisors (4)
- 1, 11, 151, 1661
- Prime factorisation
- 11 × 151
- Digit sum
- 14
- Digital root
- 5
Representations
- Decimal
- 1661
- Binary
- 11001111101
- Octal
- 3175
- Hexadecimal
- 67d
- Roman numeral
- MDCLXI
- Scientific notation
- 1.661 × 10^3
Other mathematical patterns
- Palindromic number
- Deficient number
- Semiprime
Finance & economics
Sweden's Stockholms Banco issued Europe's first banknotes in 1661 to replace copper plates weighing many kilograms. It then issued more than it could redeem and failed, establishing both the instrument and its characteristic risk.
DocumentedFinance & economicsGeography: SwedenPeriod: 1661
Common questions
Is 1661 a prime number?
No, 1661 is not prime.
What are the factors of 1661?
The factors of 1661 are 1, 11, 151, 1661.
What is 1661 in Roman numerals?
1661 in Roman numerals is MDCLXI.
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