The number 42640
42640 is a composite number with 40 divisors. Its prime factorisation is × 5 × 13 × 41. Divisors (40): 1, 2, 4, 5, 8, 10, 13, 16, 20, 26, 40, 41, 52, 65, 80, 82 … 42640.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42640: a Harshad number: divisible by its digit sum 16.
- 2
42640 is composite. Its prime factorisation is
- 3
The divisors add up to 109368; without 42640 itself that is 66728, so 42640 is abundant (66728 is more than 42640). Euler's totient φ(42640) = 15360 numbers up to 42640 share no factor with it.
- 4
The digits of 42640 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 57 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42640 = 2^{4} \times 5 \times 13 \times 41 \]42640 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 40 |
| Sum of divisors | 109368 |
| Euler totient φ(n) | 15360 |
| Square | 1818169600 |
| Cube | 77526751744000 |
| Square root | 206.494552 (= 4√2665) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 57 |
| Scientific notation | 4.264 × |
42640 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand six hundred and forty |
| Binary (base 2) | 1010011010010000 |
| Octal (base 8) | 123220 |
| Hexadecimal (base 16) | A690 |
| Base 3 | 2011111021 |
| As time | 42640 seconds = 11 h 50 min 40 s |
Is 42640 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42640 ÷ 2 = 21320) | 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 (42640 ÷ 4 = 10660) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (42640 ÷ 5 = 8528) | 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 3) | 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 (42640 ÷ 8 = 5330) | 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 (42640 ÷ 10 = 4264) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 42640 a prime number?
No. 42640 = × 5 × 13 × 41, so it is divisible by 2.
What are the factors of 42640?
1, 2, 4, 5, 8, 10, 13, 16, 20, 26, 40, 41, 52, 65, 80, 82, 104, 130, 164, 205, 208, 260, 328, 410, 520, 533, 656, 820, 1040, 1066, 1640, 2132, 2665, 3280, 4264, 5330, 8528, 10660, 21320, 42640.
What is 42640 in binary?
1010011010010000 (hexadecimal A690, octal 123220).
What is the square root of 42640?
About 206.4946, exactly 4√2665.
Is 42640 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 42640?
42640 is a Harshad number: divisible by its digit sum 16.