The number 15021
15021 is a composite number with 6 divisors. Its prime factorisation is × 1669. Divisors (6): 1, 3, 9, 1669, 5007, 15021.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 15021: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.
- 2
15021 is composite. Its prime factorisation is
- 3
The divisors add up to 21710; without 15021 itself that is 6689, so 15021 is deficient (6689 is less than 15021). Euler's totient φ(15021) = 10008 numbers up to 15021 share no factor with it.
- 4
The digits of 15021 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 63 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15021 = 3^{2} \times 1669 \]15021 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 21710 |
| Euler totient φ(n) | 10008 |
| Square | 225630441 |
| Cube | 3389194854261 |
| Square root | 122.560189 (= 3√1669) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 63 |
| Scientific notation | 1.5021 × |
15021 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand and twenty-one |
| Binary (base 2) | 11101010101101 |
| Octal (base 8) | 35255 |
| Hexadecimal (base 16) | 3AAD |
| Base 3 | 202121100 |
| As time | 15021 seconds = 4 h 10 min 21 s |
Is 15021 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 (15021 ÷ 3 = 5007) | 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 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (15021 ÷ 9 = 1669) | 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 15021 a prime number?
No. 15021 = × 1669, so it is divisible by 3.
What are the factors of 15021?
1, 3, 9, 1669, 5007, 15021.
What is 15021 in binary?
11101010101101 (hexadecimal 3AAD, octal 35255).
What is the square root of 15021?
About 122.5602, exactly 3√1669.
Is 15021 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 15021?
15021 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.