The number 31801
31801 is a composite number with 12 divisors. Its prime factorisation is × 11 × 59. Divisors (12): 1, 7, 11, 49, 59, 77, 413, 539, 649, 2891, 4543, 31801.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31801 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31801 is composite. Its prime factorisation is
- 3
The divisors add up to 41040; without 31801 itself that is 9239, so 31801 is deficient (9239 is less than 31801). Euler's totient φ(31801) = 24360 numbers up to 31801 share no factor with it.
- 4
The digits of 31801 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 129 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31801 = 7^{2} \times 11 \times 59 \]31801 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 41040 |
| Euler totient φ(n) | 24360 |
| Square | 1011303601 |
| Cube | 32160465815401 |
| Square root | 178.328349 (= 7√649) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 129 |
| Scientific notation | 3.1801 × |
31801 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand eight hundred and one |
| Binary (base 2) | 111110000111001 |
| Octal (base 8) | 76071 |
| Hexadecimal (base 16) | 7C39 |
| Base 3 | 1121121211 |
| As time | 31801 seconds = 8 h 50 min 1 s |
Is 31801 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 | Yes (31801 ÷ 7 = 4543) | 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 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 | Yes (31801 ÷ 11 = 2891) | 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 31801 a prime number?
No. 31801 = × 11 × 59, so it is divisible by 7.
What are the factors of 31801?
1, 7, 11, 49, 59, 77, 413, 539, 649, 2891, 4543, 31801.
What is 31801 in binary?
111110000111001 (hexadecimal 7C39, octal 76071).
What is the square root of 31801?
About 178.3283, exactly 7√649.
Is 31801 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 31801?
It is a composite number with 12 divisors.