The number 31540
31540 is a composite number with 24 divisors. Its prime factorisation is × 5 × 19 × 83. Divisors (24): 1, 2, 4, 5, 10, 19, 20, 38, 76, 83, 95, 166, 190, 332, 380, 415 … 31540.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31540 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31540 is composite. Its prime factorisation is
- 3
The divisors add up to 70560; without 31540 itself that is 39020, so 31540 is abundant (39020 is more than 31540). Euler's totient φ(31540) = 11808 numbers up to 31540 share no factor with it.
- 4
The digits of 31540 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 28 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31540 = 2^{2} \times 5 \times 19 \times 83 \]31540 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 70560 |
| Euler totient φ(n) | 11808 |
| Square | 994771600 |
| Cube | 31375096264000 |
| Square root | 177.595045 (= 2√7885) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 28 |
| Scientific notation | 3.154 × |
31540 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand five hundred and forty |
| Binary (base 2) | 111101100110100 |
| Octal (base 8) | 75464 |
| Hexadecimal (base 16) | 7B34 |
| Base 3 | 1121021011 |
| As time | 31540 seconds = 8 h 45 min 40 s |
Is 31540 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31540 ÷ 2 = 15770) | 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 (31540 ÷ 4 = 7885) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (31540 ÷ 5 = 6308) | 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 5) | 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 4) | 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 (31540 ÷ 10 = 3154) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | 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 31540 a prime number?
No. 31540 = × 5 × 19 × 83, so it is divisible by 2.
What are the factors of 31540?
1, 2, 4, 5, 10, 19, 20, 38, 76, 83, 95, 166, 190, 332, 380, 415, 830, 1577, 1660, 3154, 6308, 7885, 15770, 31540.
What is 31540 in binary?
111101100110100 (hexadecimal 7B34, octal 75464).
What is the square root of 31540?
About 177.5950, exactly 2√7885.
Is 31540 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 31540?
It is a composite number with 24 divisors.