  # The Number 28 Trivia Quiz

### These are mathematical properties about the number 28.

A multiple-choice quiz by hotdogPi. Estimated time: 3 mins.

Author
hotdogPi
Time
3 mins
Type
Multiple Choice
Quiz #
353,618
Updated
Dec 03 21
# Qns
10
Difficulty
Average
Avg Score
7 / 10
Plays
366
Last 3 plays: Guest 122 (2/10), Guest 211 (1/10), Guest 49 (0/10).
This quiz has 2 formats: you can play it as a or as shown below.
Scroll down to the bottom for the answer key.
1. What is the prime factorization of 28? Hint

2x2x5
2x2x7
2x3x7
2x3x5

#### NEXT>

2. Why is 28 a triangular number? Hint

It's the sum of integers from 1 to 7
It's the square root of 784
It's 3 cubed plus 1
2 is a factor of 8

#### NEXT>

3. True or false: 28 is a perfect number.

True
False

#### NEXT>

4. 28 is a sum of two cubes. Which ones? Hint

16 and 12
14 and 14
27 and 8
27 and 1

#### NEXT>

5. What is 28 in binary? Hint

11100
11000
11011
10110

#### NEXT>

6. True or false: 28 is in the Fibonacci sequence.

True
False

#### NEXT>

7. What is 28 squared? Hint

576
784
676
684

#### NEXT>

8. What is 28 in hexadecimal? Hint

2a
2c
1c
1a

#### NEXT>

9. How many unique integer factors does 28 have? Hint

5
3
6
4

#### NEXT>

10. What is the lowest square number divisible by 28? Hint

168
144
84
196

 (Optional) Create a Free FunTrivia ID to save the points you are about to earn: Select a User ID: Choose a Password: Your Email:

Quiz Answer Key and Fun Facts
1. What is the prime factorization of 28?

The prime factorization of a number tells what prime numbers multiply to that number. 2x2x5 is 20, 2x3x5 is 30, and 2x3x7 is 42.
2. Why is 28 a triangular number?

Answer: It's the sum of integers from 1 to 7

Each triangular number is the sum of all the integers between 1 and another positive integer. The list of triangular numbers begins with 1, 3, 6, 10, 15, 21, 28, 36, 45, and 55.
3. True or false: 28 is a perfect number.

28 is a perfect number because its factors (except for itself) are 1, 2, 4, 7, and 14, and they add up to 28, the number itself.
4. 28 is a sum of two cubes. Which ones?

The first numbers that are a sum of any two cubes are 1, 2, 8, 9, 16, 27, 28, 35, and 56. This assumes that 0 is a cube because it is 0^3.
5. What is 28 in binary?

"11100" means 16+8+4. "11111" means 16+8+4+2+1. "10101" means 16+4+1. So, the incorrect choices were 27 (11011), 24 (11000), and 21 (10110).
6. True or false: 28 is in the Fibonacci sequence.

The Fibonacci sequence starts with 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. You add the last two numbers to get to the current one. The sequence goes from 21 (8+13) to 34 (13+21), skipping over 28.
7. What is 28 squared?

28 cubed is 21952. 28 to the fourth power is 614656.
8. What is 28 in hexadecimal?

Hexadecimal is base 16. It uses 0 through 9 and the letters a through f as digits. A is 10, b is 11, c is 12, d is 13, e is 14, and f is 15. Instead of there being a tens place and a ones place, there is a sixteens place and a ones place. So "1c" means 16 plus 12. "2a" would be 32 plus 10, which is 42.
9. How many unique integer factors does 28 have?

Its six factors are 1, 2, 4, 7, 14, and 28. Only a square number can have an odd number of unique factors.
10. What is the lowest square number divisible by 28?

196 is 28 times 7, and is also equal to 14 squared.
Source: Author hotdogPi

This quiz was reviewed by FunTrivia editor CellarDoor before going online.
Any errors found in FunTrivia content are routinely corrected through our feedback system.
Most Recent Scores
Mar 17 2023 : Guest 122: 2/10
Mar 14 2023 : Guest 211: 1/10
Mar 14 2023 : Guest 49: 0/10
Mar 10 2023 : Guest 170: 4/10
Feb 10 2023 : Guest 83: 4/10
Feb 08 2023 : Guest 76: 4/10

Score Distribution Related Quizzes
1. Numb and Number Tough
2. The Square Root of 2 - That's Irrational! Average
3. What's My Type? Average
4. Periodic Functions Difficult