The number 21402
21402 is a composite number with 24 divisors. Its prime factorisation is 2 × × 29 × 41. Divisors (24): 1, 2, 3, 6, 9, 18, 29, 41, 58, 82, 87, 123, 174, 246, 261, 369 … 21402.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21402: a Harshad number: divisible by its digit sum 9.
- 2
21402 is composite. Its prime factorisation is
- 3
The divisors add up to 49140; without 21402 itself that is 27738, so 21402 is abundant (27738 is more than 21402). Euler's totient φ(21402) = 6720 numbers up to 21402 share no factor with it.
- 4
The digits of 21402 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 48 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21402 = 2 \times 3^{2} \times 29 \times 41 \]21402 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 49140 |
| Euler totient φ(n) | 6720 |
| Square | 458045604 |
| Cube | 9803092016808 |
| Square root | 146.294224 (= 3√2378) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 48 |
| Scientific notation | 2.1402 × |
21402 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and two |
| Binary (base 2) | 101001110011010 |
| Octal (base 8) | 51632 |
| Hexadecimal (base 16) | 539A |
| Base 3 | 1002100200 |
| As time | 21402 seconds = 5 h 56 min 42 s |
Is 21402 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21402 ÷ 2 = 10701) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21402 ÷ 3 = 7134) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (21402 ÷ 6 = 3567) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (21402 ÷ 9 = 2378) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21402 a prime number?
No. 21402 = 2 × × 29 × 41, so it is divisible by 2.
What are the factors of 21402?
1, 2, 3, 6, 9, 18, 29, 41, 58, 82, 87, 123, 174, 246, 261, 369, 522, 738, 1189, 2378, 3567, 7134, 10701, 21402.
What is 21402 in binary?
101001110011010 (hexadecimal 539A, octal 51632).
What is the square root of 21402?
About 146.2942, exactly 3√2378.
Is 21402 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 21402?
21402 is a Harshad number: divisible by its digit sum 9.