The number 51021
51021 is a composite number with 6 divisors. Its prime factorisation is × 5669. Divisors (6): 1, 3, 9, 5669, 17007, 51021.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 51021: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.
- 2
51021 is composite. Its prime factorisation is
- 3
The divisors add up to 73710; without 51021 itself that is 22689, so 51021 is deficient (22689 is less than 51021). Euler's totient φ(51021) = 34008 numbers up to 51021 share no factor with it.
- 4
The digits of 51021 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 83 steps to reach 1.
LaTeX source of the formulas on this page
\[ 51021 = 3^{2} \times 5669 \]51021 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 73710 |
| Euler totient φ(n) | 34008 |
| Square | 2603142441 |
| Cube | 132814930482261 |
| Square root | 225.878286 (= 3√5669) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 83 |
| Scientific notation | 5.1021 × |
51021 in other forms
| Form | Value |
|---|---|
| In words | fifty-one thousand and twenty-one |
| Binary (base 2) | 1100011101001101 |
| Octal (base 8) | 143515 |
| Hexadecimal (base 16) | C74D |
| Base 3 | 2120222200 |
| As time | 51021 seconds = 14 h 10 min 21 s |
Is 51021 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 (51021 ÷ 3 = 17007) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (51021 ÷ 9 = 5669) | 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 3) | 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 51021 a prime number?
No. 51021 = × 5669, so it is divisible by 3.
What are the factors of 51021?
1, 3, 9, 5669, 17007, 51021.
What is 51021 in binary?
1100011101001101 (hexadecimal C74D, octal 143515).
What is the square root of 51021?
About 225.8783, exactly 3√5669.
Is 51021 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 51021?
51021 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.