The number 2721
2721 is a composite number with 4 divisors. Its prime factorisation is 3 × 907. Divisors (4): 1, 3, 907, 2721.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2721: a semiprime: 3 × 907, the product of two primes.
- 2
2721 is composite. Its prime factorisation is
- 3
The divisors add up to 3632; without 2721 itself that is 911, so 2721 is deficient (911 is less than 2721). Euler's totient φ(2721) = 1812 numbers up to 2721 share no factor with it.
- 4
The digits of 2721 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 66 steps to reach 1.
LaTeX source of the formulas on this page
\[ 2721 = 3 \times 907 \]
2721 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 3632 |
| Euler totient φ(n) | 1812 |
| Square | 7403841 |
| Cube | 20145851361 |
| Square root | 52.163205 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 66 |
| Scientific notation | 2.721 × |
2721 in other forms
| Form | Value |
|---|---|
| In words | two thousand seven hundred and twenty-one |
| Roman numerals | MMDCCXXI |
| Binary (base 2) | 101010100001 |
| Octal (base 8) | 5241 |
| Hexadecimal (base 16) | AA1 |
| Base 3 | 10201210 |
| As time | 2721 seconds = 45 min 21 s |
Is 2721 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 (2721 ÷ 3 = 907) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | 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 5) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | 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 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2721 a prime number?
No. 2721 = 3 × 907, so it is divisible by 3.
What are the factors of 2721?
1, 3, 907, 2721.
What is 2721 in binary?
101010100001 (hexadecimal AA1, octal 5241).
What is the square root of 2721?
About 52.1632.
What is 2721 in Roman numerals?
MMDCCXXI.
Is 2721 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 2721?
2721 is a semiprime: 3 × 907, the product of two primes.