The number 21427
21427 is a composite number with 4 divisors. Its prime factorisation is 7 × 3061. Divisors (4): 1, 7, 3061, 21427.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21427: a semiprime: 7 × 3061, the product of two primes.
- 2
21427 is composite. Its prime factorisation is
- 3
The divisors add up to 24496; without 21427 itself that is 3069, so 21427 is deficient (3069 is less than 21427). Euler's totient φ(21427) = 18360 numbers up to 21427 share no factor with it.
- 4
The digits of 21427 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 30 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21427 = 7 \times 3061 \]
21427 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 24496 |
| Euler totient φ(n) | 18360 |
| Square | 459116329 |
| Cube | 9837485581483 |
| Square root | 146.379643 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 30 |
| Scientific notation | 2.1427 × |
21427 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and twenty-seven |
| Binary (base 2) | 101001110110011 |
| Octal (base 8) | 51663 |
| Hexadecimal (base 16) | 53B3 |
| Base 3 | 1002101121 |
| As time | 21427 seconds = 5 h 57 min 7 s |
Is 21427 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 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | 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 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21427 ÷ 7 = 3061) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21427 a prime number?
No. 21427 = 7 × 3061, so it is divisible by 7.
What are the factors of 21427?
1, 7, 3061, 21427.
What is 21427 in binary?
101001110110011 (hexadecimal 53B3, octal 51663).
What is the square root of 21427?
About 146.3796.
Is 21427 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 21427?
21427 is a semiprime: 7 × 3061, the product of two primes.