The number 80981
80981 is a composite number with 4 divisors. Its prime factorisation is 47 × 1723. Divisors (4): 1, 47, 1723, 80981.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 80981: a semiprime: 47 × 1723, the product of two primes.
- 2
80981 is composite. Its prime factorisation is
- 3
The divisors add up to 82752; without 80981 itself that is 1771, so 80981 is deficient (1771 is less than 80981). Euler's totient φ(80981) = 79212 numbers up to 80981 share no factor with it.
- 4
The digits of 80981 add up to 26, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 45 steps to reach 1.
LaTeX source of the formulas on this page
\[ 80981 = 47 \times 1723 \]
80981 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 82752 |
| Euler totient φ(n) | 79212 |
| Square | 6557922361 |
| Cube | 531067110716141 |
| Square root | 284.571608 |
| Digit sum / digital root | 26 / 8 |
| Collatz steps to 1 | 45 |
| Scientific notation | 8.0981 × |
80981 in other forms
| Form | Value |
|---|---|
| In words | eighty thousand nine hundred and eighty-one |
| Binary (base 2) | 10011110001010101 |
| Octal (base 8) | 236125 |
| Hexadecimal (base 16) | 13C55 |
| Base 3 | 11010002022 |
| As time | 80981 seconds = 22 h 29 min 41 s |
Is 80981 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 2) | 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 5) | 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 | No (remainder 5) | 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 | No (remainder 1) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 80981 a prime number?
No. 80981 = 47 × 1723, so it is divisible by 47.
What are the factors of 80981?
1, 47, 1723, 80981.
What is 80981 in binary?
10011110001010101 (hexadecimal 13C55, octal 236125).
What is the square root of 80981?
About 284.5716.
Is 80981 divisible by 3?
No. Its digits add up to 26, which is not a multiple of 3.
What is special about the number 80981?
80981 is a semiprime: 47 × 1723, the product of two primes.