The number 31971
31971 is a composite number with 4 divisors. Its prime factorisation is 3 × 10657. Divisors (4): 1, 3, 10657, 31971.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31971: a semiprime: 3 × 10657, the product of two primes.
- 2
31971 is composite. Its prime factorisation is
- 3
The divisors add up to 42632; without 31971 itself that is 10661, so 31971 is deficient (10661 is less than 31971). Euler's totient φ(31971) = 21312 numbers up to 31971 share no factor with it.
- 4
The digits of 31971 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 54 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31971 = 3 \times 10657 \]
31971 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 42632 |
| Euler totient φ(n) | 21312 |
| Square | 1022144841 |
| Cube | 32678992711611 |
| Square root | 178.804362 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 54 |
| Scientific notation | 3.1971 × |
31971 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and seventy-one |
| Binary (base 2) | 111110011100011 |
| Octal (base 8) | 76343 |
| Hexadecimal (base 16) | 7CE3 |
| Base 3 | 1121212010 |
| As time | 31971 seconds = 8 h 52 min 51 s |
Is 31971 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 | Yes (31971 ÷ 3 = 10657) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | 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 3) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | 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 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31971 a prime number?
No. 31971 = 3 × 10657, so it is divisible by 3.
What are the factors of 31971?
1, 3, 10657, 31971.
What is 31971 in binary?
111110011100011 (hexadecimal 7CE3, octal 76343).
What is the square root of 31971?
About 178.8044.
Is 31971 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 31971?
31971 is a semiprime: 3 × 10657, the product of two primes.