The number 2691
2691 is a composite number with 12 divisors. Its prime factorisation is × 13 × 23. Divisors (12): 1, 3, 9, 13, 23, 39, 69, 117, 207, 299, 897, 2691.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
2691 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
2691 is composite. Its prime factorisation is
- 3
The divisors add up to 4368; without 2691 itself that is 1677, so 2691 is deficient (1677 is less than 2691). Euler's totient φ(2691) = 1584 numbers up to 2691 share no factor with it.
- 4
The digits of 2691 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 115 steps to reach 1.
LaTeX source of the formulas on this page
\[ 2691 = 3^{2} \times 13 \times 23 \]2691 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 4368 |
| Euler totient φ(n) | 1584 |
| Square | 7241481 |
| Cube | 19486825371 |
| Square root | 51.874849 (= 3√299) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 115 |
| Scientific notation | 2.691 × |
2691 in other forms
| Form | Value |
|---|---|
| In words | two thousand six hundred and ninety-one |
| Roman numerals | MMDCXCI |
| Binary (base 2) | 101010000011 |
| Octal (base 8) | 5203 |
| Hexadecimal (base 16) | A83 |
| Base 3 | 10200200 |
| As time | 2691 seconds = 44 min 51 s |
Is 2691 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 | Yes (2691 ÷ 3 = 897) | 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 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | 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 | No (remainder 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (2691 ÷ 9 = 299) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2691 a prime number?
No. 2691 = × 13 × 23, so it is divisible by 3.
What are the factors of 2691?
1, 3, 9, 13, 23, 39, 69, 117, 207, 299, 897, 2691.
What is 2691 in binary?
101010000011 (hexadecimal A83, octal 5203).
What is the square root of 2691?
About 51.8748, exactly 3√299.
What is 2691 in Roman numerals?
MMDCXCI.
Is 2691 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 2691?
It is a composite number with 12 divisors.