The number 5121
5121 is a composite number with 6 divisors. Its prime factorisation is × 569. Divisors (6): 1, 3, 9, 569, 1707, 5121.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 5121: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.
- 2
5121 is composite. Its prime factorisation is
- 3
The divisors add up to 7410; without 5121 itself that is 2289, so 5121 is deficient (2289 is less than 5121). Euler's totient φ(5121) = 3408 numbers up to 5121 share no factor with it.
- 4
The digits of 5121 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 41 steps to reach 1.
LaTeX source of the formulas on this page
\[ 5121 = 3^{2} \times 569 \]5121 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 7410 |
| Euler totient φ(n) | 3408 |
| Square | 26224641 |
| Cube | 134296386561 |
| Square root | 71.561163 (= 3√569) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 41 |
| Scientific notation | 5.121 × |
5121 in other forms
| Form | Value |
|---|---|
| In words | five thousand one hundred and twenty-one |
| Binary (base 2) | 1010000000001 |
| Octal (base 8) | 12001 |
| Hexadecimal (base 16) | 1401 |
| Base 3 | 21000200 |
| As time | 5121 seconds = 1 h 25 min 21 s |
Is 5121 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 (5121 ÷ 3 = 1707) | 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 4) | 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 | Yes (5121 ÷ 9 = 569) | 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 6) | 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 5121 a prime number?
No. 5121 = × 569, so it is divisible by 3.
What are the factors of 5121?
1, 3, 9, 569, 1707, 5121.
What is 5121 in binary?
1010000000001 (hexadecimal 1401, octal 12001).
What is the square root of 5121?
About 71.5612, exactly 3√569.
Is 5121 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 5121?
5121 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.