The number 31000
31000 is a composite number with 32 divisors. Its prime factorisation is × × 31. Divisors (32): 1, 2, 4, 5, 8, 10, 20, 25, 31, 40, 50, 62, 100, 124, 125, 155 … 31000.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31000: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 4.
- 2
31000 is composite. Its prime factorisation is
- 3
The divisors add up to 74880; without 31000 itself that is 43880, so 31000 is abundant (43880 is more than 31000). Euler's totient φ(31000) = 12000 numbers up to 31000 share no factor with it.
- 4
The digits of 31000 add up to 4, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 54 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31000 = 2^{3} \times 5^{3} \times 31 \]31000 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 74880 |
| Euler totient φ(n) | 12000 |
| Square | 961000000 |
| Cube | 29791000000000 |
| Square root | 176.068169 (= 10√310) |
| Digit sum / digital root | 4 / 4 |
| Collatz steps to 1 | 54 |
| Scientific notation | 3.1 × |
31000 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand |
| Binary (base 2) | 111100100011000 |
| Octal (base 8) | 74430 |
| Hexadecimal (base 16) | 7918 |
| Base 3 | 1120112011 |
| As time | 31000 seconds = 8 h 36 min 40 s |
Is 31000 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31000 ÷ 2 = 15500) | 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 | Yes (31000 ÷ 4 = 7750) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (31000 ÷ 5 = 6200) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 | Yes (31000 ÷ 8 = 3875) | 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 | Yes (31000 ÷ 10 = 3100) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31000 a prime number?
No. 31000 = × × 31, so it is divisible by 2.
What are the factors of 31000?
1, 2, 4, 5, 8, 10, 20, 25, 31, 40, 50, 62, 100, 124, 125, 155, 200, 248, 250, 310, 500, 620, 775, 1000, 1240, 1550, 3100, 3875, 6200, 7750, 15500, 31000.
What is 31000 in binary?
111100100011000 (hexadecimal 7918, octal 74430).
What is the square root of 31000?
About 176.0682, exactly 10√310.
Is 31000 divisible by 3?
No. Its digits add up to 4, which is not a multiple of 3.
What is special about the number 31000?
31000 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 4.