The number 67981
67981 is a composite number with 4 divisors. Its prime factorisation is 157 × 433. Divisors (4): 1, 157, 433, 67981.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 67981: a semiprime: 157 × 433, the product of two primes.
- 2
67981 is composite. Its prime factorisation is
- 3
The divisors add up to 68572; without 67981 itself that is 591, so 67981 is deficient (591 is less than 67981). Euler's totient φ(67981) = 67392 numbers up to 67981 share no factor with it.
- 4
The digits of 67981 add up to 31, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 130 steps to reach 1.
LaTeX source of the formulas on this page
\[ 67981 = 157 \times 433 \]
67981 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 68572 |
| Euler totient φ(n) | 67392 |
| Square | 4621416361 |
| Cube | 314168505637141 |
| Square root | 260.731663 |
| Digit sum / digital root | 31 / 4 |
| Collatz steps to 1 | 130 |
| Scientific notation | 6.7981 × |
67981 in other forms
| Form | Value |
|---|---|
| In words | sixty-seven thousand nine hundred and eighty-one |
| Binary (base 2) | 10000100110001101 |
| Octal (base 8) | 204615 |
| Hexadecimal (base 16) | 1098D |
| Base 3 | 10110020211 |
| As time | 67981 seconds = 18 h 53 min 1 s |
Is 67981 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 | No (remainder 1) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 67981 a prime number?
No. 67981 = 157 × 433, so it is divisible by 157.
What are the factors of 67981?
1, 157, 433, 67981.
What is 67981 in binary?
10000100110001101 (hexadecimal 1098D, octal 204615).
What is the square root of 67981?
About 260.7317.
Is 67981 divisible by 3?
No. Its digits add up to 31, which is not a multiple of 3.
What is special about the number 67981?
67981 is a semiprime: 157 × 433, the product of two primes.