1900
1900 was not a leap year, and port 1900 carries UPnP device discovery.
- Even
- Composite
Where 1900 fits
Why 1900 is special
The two are unrelated. Years divisible by 100 skip the leap day unless also divisible by 400, so 1900 had no 29 February while 2000 did. A great deal of software has been written that gets this wrong, because the exception only bites twice in four centuries.
1900 is part of
Factors & digit properties
- Divisors (18)
- 1, 2, 4, 5, 10, 19, 20, 25, 38, 50, 76, 95, 100, 190, 380, 475, 950, 1900
- Prime factorisation
- 2^2 × 5^2 × 19
- Digit sum
- 10
- Digital root
- 1
Representations
- Decimal
- 1900
- Binary
- 11101101100
- Octal
- 3554
- Hexadecimal
- 76c
- Roman numeral
- MCM
- Scientific notation
- 1.900 × 10^3
Other mathematical patterns
- Abundant number
- Happy number
- Harshad (Niven) number
Related numbers & connections
1900 was not a leap year and 2000 was. The rule skips the leap day in century years unless they divide by 400, which means the exception has been tested exactly once since the calendar was adopted.
View 2000 →Science
A year divisible by 100 is not a leap year unless it is also divisible by 400. So 1900 had no 29 February and 2000 did — and any software tested only around 2000 got the right answer for the wrong reason. The next test is 2100.
DocumentedScience
Common questions
Is 1900 a prime number?
No, 1900 is not prime.
What are the factors of 1900?
The factors of 1900 are 1, 2, 4, 5, 10, 19, 20, 25, 38, 50, 76, 95, 100, 190, 380, 475, 950, 1900.
What is 1900 in Roman numerals?
1900 in Roman numerals is MCM.
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