The number 72820
72820 is a composite number with 24 divisors. Its prime factorisation is × 5 × 11 × 331. Divisors (24): 1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110, 220, 331, 662, 1324, 1655 … 72820.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
72820 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
72820 is composite. Its prime factorisation is
- 3
The divisors add up to 167328; without 72820 itself that is 94508, so 72820 is abundant (94508 is more than 72820). Euler's totient φ(72820) = 26400 numbers up to 72820 share no factor with it.
- 4
The digits of 72820 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 187 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72820 = 2^{2} \times 5 \times 11 \times 331 \]72820 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 167328 |
| Euler totient φ(n) | 26400 |
| Square | 5302752400 |
| Cube | 386146429768000 |
| Square root | 269.851811 (= 2√18205) |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 187 |
| Scientific notation | 7.282 × |
72820 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand eight hundred and twenty |
| Binary (base 2) | 10001110001110100 |
| Octal (base 8) | 216164 |
| Hexadecimal (base 16) | 11C74 |
| Base 3 | 10200220001 |
| As time | 72820 seconds = 20 h 13 min 40 s |
Is 72820 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (72820 ÷ 2 = 36410) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (72820 ÷ 4 = 18205) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (72820 ÷ 5 = 14564) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 | No (remainder 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (72820 ÷ 10 = 7282) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (72820 ÷ 11 = 6620) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72820 a prime number?
No. 72820 = × 5 × 11 × 331, so it is divisible by 2.
What are the factors of 72820?
1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110, 220, 331, 662, 1324, 1655, 3310, 3641, 6620, 7282, 14564, 18205, 36410, 72820.
What is 72820 in binary?
10001110001110100 (hexadecimal 11C74, octal 216164).
What is the square root of 72820?
About 269.8518, exactly 2√18205.
Is 72820 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 72820?
It is a composite number with 24 divisors.