The number 2491
2491 is a composite number with 4 divisors. Its prime factorisation is 47 × 53. Divisors (4): 1, 47, 53, 2491.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2491: a semiprime: 47 × 53, the product of two primes.
- 2
2491 is composite. Its prime factorisation is
- 3
The divisors add up to 2592; without 2491 itself that is 101, so 2491 is deficient (101 is less than 2491). Euler's totient φ(2491) = 2392 numbers up to 2491 share no factor with it.
- 4
The digits of 2491 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
\[ 2491 = 47 \times 53 \]
2491 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 2592 |
| Euler totient φ(n) | 2392 |
| Square | 6205081 |
| Cube | 15456856771 |
| Square root | 49.909919 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 102 |
| Scientific notation | 2.491 × |
2491 in other forms
| Form | Value |
|---|---|
| In words | two thousand four hundred and ninety-one |
| Roman numerals | MMCDXCI |
| Binary (base 2) | 100110111011 |
| Octal (base 8) | 4673 |
| Hexadecimal (base 16) | 9BB |
| Base 3 | 10102021 |
| As time | 2491 seconds = 41 min 31 s |
Is 2491 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 1) | 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 1) | 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 3) | 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 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2491 a prime number?
No. 2491 = 47 × 53, so it is divisible by 47.
What are the factors of 2491?
1, 47, 53, 2491.
What is 2491 in binary?
100110111011 (hexadecimal 9BB, octal 4673).
What is the square root of 2491?
About 49.9099.
What is 2491 in Roman numerals?
MMCDXCI.
Is 2491 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 2491?
2491 is a semiprime: 47 × 53, the product of two primes.