The number 72920
72920 is a composite number with 16 divisors. Its prime factorisation is × 5 × 1823. Divisors (16): 1, 2, 4, 5, 8, 10, 20, 40, 1823, 3646, 7292, 9115, 14584, 18230, 36460, 72920.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 72920: a Harshad number: divisible by its digit sum 20.
- 2
72920 is composite. Its prime factorisation is
- 3
The divisors add up to 164160; without 72920 itself that is 91240, so 72920 is abundant (91240 is more than 72920). Euler's totient φ(72920) = 29152 numbers up to 72920 share no factor with it.
- 4
The digits of 72920 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 156 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72920 = 2^{3} \times 5 \times 1823 \]72920 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 164160 |
| Euler totient φ(n) | 29152 |
| Square | 5317326400 |
| Cube | 387739441088000 |
| Square root | 270.037034 (= 2√18230) |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 156 |
| Scientific notation | 7.292 × |
72920 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand nine hundred and twenty |
| Binary (base 2) | 10001110011011000 |
| Octal (base 8) | 216330 |
| Hexadecimal (base 16) | 11CD8 |
| Base 3 | 10201000202 |
| As time | 72920 seconds = 20 h 15 min 20 s |
Is 72920 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (72920 ÷ 2 = 36460) | 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 (72920 ÷ 4 = 18230) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (72920 ÷ 5 = 14584) | 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 (72920 ÷ 8 = 9115) | 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 (72920 ÷ 10 = 7292) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | 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 72920 a prime number?
No. 72920 = × 5 × 1823, so it is divisible by 2.
What are the factors of 72920?
1, 2, 4, 5, 8, 10, 20, 40, 1823, 3646, 7292, 9115, 14584, 18230, 36460, 72920.
What is 72920 in binary?
10001110011011000 (hexadecimal 11CD8, octal 216330).
What is the square root of 72920?
About 270.0370, exactly 2√18230.
Is 72920 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 72920?
72920 is a Harshad number: divisible by its digit sum 20.