The number 9920
9920 is a composite number with 28 divisors. Its prime factorisation is × 5 × 31. Divisors (28): 1, 2, 4, 5, 8, 10, 16, 20, 31, 32, 40, 62, 64, 80, 124, 155 … 9920.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 9920: a Harshad number: divisible by its digit sum 20.
- 2
9920 is composite. Its prime factorisation is
- 3
The divisors add up to 24384; without 9920 itself that is 14464, so 9920 is abundant (14464 is more than 9920). Euler's totient φ(9920) = 3840 numbers up to 9920 share no factor with it.
- 4
The digits of 9920 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 91 steps to reach 1.
LaTeX source of the formulas on this page
\[ 9920 = 2^{6} \times 5 \times 31 \]9920 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 28 |
| Sum of divisors | 24384 |
| Euler totient φ(n) | 3840 |
| Square | 98406400 |
| Cube | 976191488000 |
| Square root | 99.599197 (= 8√155) |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 91 |
| Scientific notation | 9.92 × |
9920 in other forms
| Form | Value |
|---|---|
| In words | nine thousand nine hundred and twenty |
| Binary (base 2) | 10011011000000 |
| Octal (base 8) | 23300 |
| Hexadecimal (base 16) | 26C0 |
| Base 3 | 111121102 |
| As time | 9920 seconds = 2 h 45 min 20 s |
Is 9920 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (9920 ÷ 2 = 4960) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (9920 ÷ 4 = 2480) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (9920 ÷ 5 = 1984) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | Yes (9920 ÷ 8 = 1240) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (9920 ÷ 10 = 992) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 9920 a prime number?
No. 9920 = × 5 × 31, so it is divisible by 2.
What are the factors of 9920?
1, 2, 4, 5, 8, 10, 16, 20, 31, 32, 40, 62, 64, 80, 124, 155, 160, 248, 310, 320, 496, 620, 992, 1240, 1984, 2480, 4960, 9920.
What is 9920 in binary?
10011011000000 (hexadecimal 26C0, octal 23300).
What is the square root of 9920?
About 99.5992, exactly 8√155.
Is 9920 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 9920?
9920 is a Harshad number: divisible by its digit sum 20.