28
Number 28: Properties, Factors, and Mathematical Facts
Short answer
The number 28 is an even composite number with 6 positive divisors. Its prime factorization is 2² × 7. It is also a perfect number and a triangular number, which gives it several notable mathematical relationships.
Is 28 prime?
ClassificationCompositeParityEvenDivisor count6AbundancePerfect
What is the prime factorization of 28?
Prime factorization
2 squared times 7
What are the divisors of 28?
Divisor count
6
Divisor sum
56
Proper divisor sum
28
- 1
- 2
- 4
- 7
- 14
- 28
How is 28 classified?
Prime
CompositeLearn more →
Perfect square
No
Perfect cube
No
Fibonacci
No
Triangular
YesLearn more →
Power of two
No
How is 28 represented in other numeral systems?
Roots and powers
Square root
5.291503 Approximate
Cube root
3.036589 Approximate
Nearest lower square
25
Nearest higher square
36
Nearest lower cube
27
Nearest higher cube
64
Sequence position
Triangular
Index: 7
What are the digit properties of 28?
Which numbers are related to 28?
Why these results are true
- 28 is composite because it has positive divisors other than 1 and itself.
- 28 is triangular because it equals 7×(7+1)/2.
Compare this number
FAQ for 28
- Is 28 prime?
- No
- What is the prime factorization of 28?
- 2² × 7
- Is 28 a perfect square?
- No
- What is 28 in binary?
- 11100
- What is 28 in Roman numerals?
- XXVIII