The number 15640
15640 is a composite number with 32 divisors. Its prime factorisation is × 5 × 17 × 23. Divisors (32): 1, 2, 4, 5, 8, 10, 17, 20, 23, 34, 40, 46, 68, 85, 92, 115 … 15640.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
15640 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
15640 is composite. Its prime factorisation is
- 3
The divisors add up to 38880; without 15640 itself that is 23240, so 15640 is abundant (23240 is more than 15640). Euler's totient φ(15640) = 5632 numbers up to 15640 share no factor with it.
- 4
The digits of 15640 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 102 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15640 = 2^{3} \times 5 \times 17 \times 23 \]15640 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 38880 |
| Euler totient φ(n) | 5632 |
| Square | 244609600 |
| Cube | 3825694144000 |
| Square root | 125.059986 (= 2√3910) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 102 |
| Scientific notation | 1.564 × |
15640 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand six hundred and forty |
| Binary (base 2) | 11110100011000 |
| Octal (base 8) | 36430 |
| Hexadecimal (base 16) | 3D18 |
| Base 3 | 210110021 |
| As time | 15640 seconds = 4 h 20 min 40 s |
Is 15640 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (15640 ÷ 2 = 7820) | 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 (15640 ÷ 4 = 3910) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (15640 ÷ 5 = 3128) | 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 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 | Yes (15640 ÷ 8 = 1955) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (15640 ÷ 10 = 1564) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | 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 15640 a prime number?
No. 15640 = × 5 × 17 × 23, so it is divisible by 2.
What are the factors of 15640?
1, 2, 4, 5, 8, 10, 17, 20, 23, 34, 40, 46, 68, 85, 92, 115, 136, 170, 184, 230, 340, 391, 460, 680, 782, 920, 1564, 1955, 3128, 3910, 7820, 15640.
What is 15640 in binary?
11110100011000 (hexadecimal 3D18, octal 36430).
What is the square root of 15640?
About 125.0600, exactly 2√3910.
Is 15640 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 15640?
It is a composite number with 32 divisors.