The number 79920
79920 is a composite number with 80 divisors. Its prime factorisation is × × 5 × 37. Divisors (80): 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 27 … 79920.
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How to work it out
- 1
What is special about 79920: a Harshad number: divisible by its digit sum 27.
- 2
79920 is composite. Its prime factorisation is
- 3
The divisors add up to 282720; without 79920 itself that is 202800, so 79920 is abundant (202800 is more than 79920). Euler's totient φ(79920) = 20736 numbers up to 79920 share no factor with it.
- 4
The digits of 79920 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 94 steps to reach 1.
LaTeX source of the formulas on this page
\[ 79920 = 2^{4} \times 3^{3} \times 5 \times 37 \]79920 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 80 |
| Sum of divisors | 282720 |
| Euler totient φ(n) | 20736 |
| Square | 6387206400 |
| Cube | 510465535488000 |
| Square root | 282.701256 (= 12√555) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 94 |
| Scientific notation | 7.992 × |
79920 in other forms
| Form | Value |
|---|---|
| In words | seventy-nine thousand nine hundred and twenty |
| Binary (base 2) | 10011100000110000 |
| Octal (base 8) | 234060 |
| Hexadecimal (base 16) | 13830 |
| Base 3 | 11001122000 |
| As time | 79920 seconds = 22 h 12 min 0 s |
Is 79920 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (79920 ÷ 2 = 39960) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (79920 ÷ 3 = 26640) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (79920 ÷ 4 = 19980) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (79920 ÷ 5 = 15984) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (79920 ÷ 6 = 13320) | 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 (79920 ÷ 8 = 9990) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (79920 ÷ 9 = 8880) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (79920 ÷ 10 = 7992) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (79920 ÷ 12 = 6660) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 79920 a prime number?
No. 79920 = × × 5 × 37, so it is divisible by 2.
What are the factors of 79920?
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 27, 30, 36, 37, 40, 45, 48, 54, 60, 72, 74, 80, 90, 108, 111, 120, 135, 144, 148, 180, 185, 216, 222, 240, 270, 296, 333, 360, 370, 432, 444, 540, 555, 592, 666, 720, 740, 888, 999, 1080, 1110, 1332, 1480, 1665, 1776, 1998, 2160, 2220, 2664, 2960, 3330, 3996, 4440, 4995, 5328, 6660, 7992, 8880, 9990, 13320, 15984, 19980, 26640, 39960, 79920.
What is 79920 in binary?
10011100000110000 (hexadecimal 13830, octal 234060).
What is the square root of 79920?
About 282.7013, exactly 12√555.
Is 79920 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 79920?
79920 is a Harshad number: divisible by its digit sum 27.