The number 31961
31961 is a composite number with 4 divisors. Its prime factorisation is 31 × 1031. Divisors (4): 1, 31, 1031, 31961.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31961: a semiprime: 31 × 1031, the product of two primes.
- 2
31961 is composite. Its prime factorisation is
- 3
The divisors add up to 33024; without 31961 itself that is 1063, so 31961 is deficient (1063 is less than 31961). Euler's totient φ(31961) = 30900 numbers up to 31961 share no factor with it.
- 4
The digits of 31961 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 85 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31961 = 31 \times 1031 \]
31961 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 33024 |
| Euler totient φ(n) | 30900 |
| Square | 1021505521 |
| Cube | 32648337956681 |
| Square root | 178.776397 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 85 |
| Scientific notation | 3.1961 × |
31961 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and sixty-one |
| Binary (base 2) | 111110011011001 |
| Octal (base 8) | 76331 |
| Hexadecimal (base 16) | 7CD9 |
| Base 3 | 1121211202 |
| As time | 31961 seconds = 8 h 52 min 41 s |
Is 31961 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 6) | 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 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 6) | 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 31961 a prime number?
No. 31961 = 31 × 1031, so it is divisible by 31.
What are the factors of 31961?
1, 31, 1031, 31961.
What is 31961 in binary?
111110011011001 (hexadecimal 7CD9, octal 76331).
What is the square root of 31961?
About 178.7764.
Is 31961 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 31961?
31961 is a semiprime: 31 × 1031, the product of two primes.