The number 71720
71720 is a composite number with 32 divisors. Its prime factorisation is × 5 × 11 × 163. Divisors (32): 1, 2, 4, 5, 8, 10, 11, 20, 22, 40, 44, 55, 88, 110, 163, 220 … 71720.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 71720: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
71720 is composite. Its prime factorisation is
- 3
The divisors add up to 177120; without 71720 itself that is 105400, so 71720 is abundant (105400 is more than 71720). Euler's totient φ(71720) = 25920 numbers up to 71720 share no factor with it.
- 4
The digits of 71720 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 50 steps to reach 1.
LaTeX source of the formulas on this page
\[ 71720 = 2^{3} \times 5 \times 11 \times 163 \]71720 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 177120 |
| Euler totient φ(n) | 25920 |
| Square | 5143758400 |
| Cube | 368910352448000 |
| Square root | 267.805900 (= 2√17930) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 50 |
| Scientific notation | 7.172 × |
71720 in other forms
| Form | Value |
|---|---|
| In words | seventy-one thousand seven hundred and twenty |
| Binary (base 2) | 10001100000101000 |
| Octal (base 8) | 214050 |
| Hexadecimal (base 16) | 11828 |
| Base 3 | 10122101022 |
| As time | 71720 seconds = 19 h 55 min 20 s |
Is 71720 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (71720 ÷ 2 = 35860) | 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 (71720 ÷ 4 = 17930) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (71720 ÷ 5 = 14344) | 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 5) | 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 (71720 ÷ 8 = 8965) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (71720 ÷ 10 = 7172) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (71720 ÷ 11 = 6520) | 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 71720 a prime number?
No. 71720 = × 5 × 11 × 163, so it is divisible by 2.
What are the factors of 71720?
1, 2, 4, 5, 8, 10, 11, 20, 22, 40, 44, 55, 88, 110, 163, 220, 326, 440, 652, 815, 1304, 1630, 1793, 3260, 3586, 6520, 7172, 8965, 14344, 17930, 35860, 71720.
What is 71720 in binary?
10001100000101000 (hexadecimal 11828, octal 214050).
What is the square root of 71720?
About 267.8059, exactly 2√17930.
Is 71720 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 71720?
71720 is a happy number: repeatedly adding the squares of its digits reaches 1.