The number 2687
2687 is a twin prime (2687 and 2689 are both prime) and the 390th prime number. Its only divisors are 1 and 2687.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2687: a twin prime (2687 and 2689 are both prime); the 390th prime number.
- 2
2687 is prime, so its only factors are 1 and 2687. It is the 390th prime; the next prime is 2689 and the one before is 2683.
- 3
The divisors add up to 2688; without 2687 itself that is 1, so 2687 is deficient (1 is less than 2687). Euler's totient φ(2687) = 2686 numbers up to 2687 share no factor with it.
- 4
The digits of 2687 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 97 steps to reach 1.
2687 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 2688 |
| Euler totient φ(n) | 2686 |
| Square | 7219969 |
| Cube | 19400056703 |
| Square root | 51.836281 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 97 |
| Scientific notation | 2.687 × |
2687 in other forms
| Form | Value |
|---|---|
| In words | two thousand six hundred and eighty-seven |
| Roman numerals | MMDCLXXXVII |
| Binary (base 2) | 101001111111 |
| Octal (base 8) | 5177 |
| Hexadecimal (base 16) | A7F |
| Base 3 | 10200112 |
| As time | 2687 seconds = 44 min 47 s |
Is 2687 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 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | 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 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2687 a prime number?
Yes. 2687 is divisible only by 1 and itself.
What are the factors of 2687?
1, 2687.
What is 2687 in binary?
101001111111 (hexadecimal A7F, octal 5177).
What is the square root of 2687?
About 51.8363.
What is 2687 in Roman numerals?
MMDCLXXXVII.
Is 2687 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 2687?
2687 is a twin prime (2687 and 2689 are both prime); the 390th prime number.