The number 61761
61761 is a composite number with 16 divisors. Its prime factorisation is 3 × 7 × 17 × 173. Divisors (16): 1, 3, 7, 17, 21, 51, 119, 173, 357, 519, 1211, 2941, 3633, 8823, 20587, 61761.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 61761: a Harshad number: divisible by its digit sum 21.
- 2
61761 is composite. Its prime factorisation is
- 3
The divisors add up to 100224; without 61761 itself that is 38463, so 61761 is deficient (38463 is less than 61761). Euler's totient φ(61761) = 33024 numbers up to 61761 share no factor with it.
- 4
The digits of 61761 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 60 steps to reach 1.
LaTeX source of the formulas on this page
\[ 61761 = 3 \times 7 \times 17 \times 173 \]
61761 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 100224 |
| Euler totient φ(n) | 33024 |
| Square | 3814421121 |
| Cube | 235582462854081 |
| Square root | 248.517605 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 60 |
| Scientific notation | 6.1761 × |
61761 in other forms
| Form | Value |
|---|---|
| In words | sixty-one thousand seven hundred and sixty-one |
| Binary (base 2) | 1111000101000001 |
| Octal (base 8) | 170501 |
| Hexadecimal (base 16) | F141 |
| Base 3 | 10010201110 |
| As time | 61761 seconds = 17 h 9 min 21 s |
Is 61761 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (61761 ÷ 3 = 20587) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (61761 ÷ 7 = 8823) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 61761 a prime number?
No. 61761 = 3 × 7 × 17 × 173, so it is divisible by 3.
What are the factors of 61761?
1, 3, 7, 17, 21, 51, 119, 173, 357, 519, 1211, 2941, 3633, 8823, 20587, 61761.
What is 61761 in binary?
1111000101000001 (hexadecimal F141, octal 170501).
What is the square root of 61761?
About 248.5176.
Is 61761 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 61761?
61761 is a Harshad number: divisible by its digit sum 21.