The number 83981
83981 is a composite number with 4 divisors. Its prime factorisation is 137 × 613. Divisors (4): 1, 137, 613, 83981.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 83981: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 137 × 613, the product of two primes.
- 2
83981 is composite. Its prime factorisation is
- 3
The divisors add up to 84732; without 83981 itself that is 751, so 83981 is deficient (751 is less than 83981). Euler's totient φ(83981) = 83232 numbers up to 83981 share no factor with it.
- 4
The digits of 83981 add up to 29, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 151 steps to reach 1.
LaTeX source of the formulas on this page
\[ 83981 = 137 \times 613 \]
83981 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 84732 |
| Euler totient φ(n) | 83232 |
| Square | 7052808361 |
| Cube | 592301898965141 |
| Square root | 289.794755 |
| Digit sum / digital root | 29 / 2 |
| Collatz steps to 1 | 151 |
| Scientific notation | 8.3981 × |
83981 in other forms
| Form | Value |
|---|---|
| In words | eighty-three thousand nine hundred and eighty-one |
| Binary (base 2) | 10100100000001101 |
| Octal (base 8) | 244015 |
| Hexadecimal (base 16) | 1480D |
| Base 3 | 11021012102 |
| As time | 83981 seconds = 23 h 19 min 41 s |
Is 83981 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 2) | 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 2) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 83981 a prime number?
No. 83981 = 137 × 613, so it is divisible by 137.
What are the factors of 83981?
1, 137, 613, 83981.
What is 83981 in binary?
10100100000001101 (hexadecimal 1480D, octal 244015).
What is the square root of 83981?
About 289.7948.
Is 83981 divisible by 3?
No. Its digits add up to 29, which is not a multiple of 3.
What is special about the number 83981?
83981 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 137 × 613, the product of two primes.