The number 61720
61720 is a composite number with 16 divisors. Its prime factorisation is × 5 × 1543. Divisors (16): 1, 2, 4, 5, 8, 10, 20, 40, 1543, 3086, 6172, 7715, 12344, 15430, 30860, 61720.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
61720 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
61720 is composite. Its prime factorisation is
- 3
The divisors add up to 138960; without 61720 itself that is 77240, so 61720 is abundant (77240 is more than 61720). Euler's totient φ(61720) = 24672 numbers up to 61720 share no factor with it.
- 4
The digits of 61720 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 55 steps to reach 1.
LaTeX source of the formulas on this page
\[ 61720 = 2^{3} \times 5 \times 1543 \]61720 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 138960 |
| Euler totient φ(n) | 24672 |
| Square | 3809358400 |
| Cube | 235113600448000 |
| Square root | 248.435102 (= 2√15430) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 55 |
| Scientific notation | 6.172 × |
61720 in other forms
| Form | Value |
|---|---|
| In words | sixty-one thousand seven hundred and twenty |
| Binary (base 2) | 1111000100011000 |
| Octal (base 8) | 170430 |
| Hexadecimal (base 16) | F118 |
| Base 3 | 10010122221 |
| As time | 61720 seconds = 17 h 8 min 40 s |
Is 61720 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (61720 ÷ 2 = 30860) | 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 (61720 ÷ 4 = 15430) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (61720 ÷ 5 = 12344) | 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 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 (61720 ÷ 8 = 7715) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (61720 ÷ 10 = 6172) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | 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 61720 a prime number?
No. 61720 = × 5 × 1543, so it is divisible by 2.
What are the factors of 61720?
1, 2, 4, 5, 8, 10, 20, 40, 1543, 3086, 6172, 7715, 12344, 15430, 30860, 61720.
What is 61720 in binary?
1111000100011000 (hexadecimal F118, octal 170430).
What is the square root of 61720?
About 248.4351, exactly 2√15430.
Is 61720 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 61720?
It is a composite number with 16 divisors.