The number 4721
4721 is a twin prime (4721 and 4723 are both prime) and the 636th prime number. Its only divisors are 1 and 4721.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 4721: a twin prime (4721 and 4723 are both prime); the 636th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
4721 is prime, so its only factors are 1 and 4721. It is the 636th prime; the next prime is 4723 and the one before is 4703.
- 3
The divisors add up to 4722; without 4721 itself that is 1, so 4721 is deficient (1 is less than 4721). Euler's totient φ(4721) = 4720 numbers up to 4721 share no factor with it.
- 4
The digits of 4721 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 121 steps to reach 1.
4721 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 4722 |
| Euler totient φ(n) | 4720 |
| Square | 22287841 |
| Cube | 105220897361 |
| Square root | 68.709534 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 121 |
| Scientific notation | 4.721 × |
4721 in other forms
| Form | Value |
|---|---|
| In words | four thousand seven hundred and twenty-one |
| Binary (base 2) | 1001001110001 |
| Octal (base 8) | 11161 |
| Hexadecimal (base 16) | 1271 |
| Base 3 | 20110212 |
| As time | 4721 seconds = 1 h 18 min 41 s |
Is 4721 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 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 5) | 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 1) | 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 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 4721 a prime number?
Yes. 4721 is divisible only by 1 and itself.
What are the factors of 4721?
1, 4721.
What is 4721 in binary?
1001001110001 (hexadecimal 1271, octal 11161).
What is the square root of 4721?
About 68.7095.
Is 4721 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 4721?
4721 is a twin prime (4721 and 4723 are both prime); the 636th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.