The number 21437
21437 is a composite number with 8 divisors. Its prime factorisation is 13 × 17 × 97. Divisors (8): 1, 13, 17, 97, 221, 1261, 1649, 21437.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21437: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 17.
- 2
21437 is composite. Its prime factorisation is
- 3
The divisors add up to 24696; without 21437 itself that is 3259, so 21437 is deficient (3259 is less than 21437). Euler's totient φ(21437) = 18432 numbers up to 21437 share no factor with it.
- 4
The digits of 21437 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 193 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21437 = 13 \times 17 \times 97 \]
21437 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 24696 |
| Euler totient φ(n) | 18432 |
| Square | 459544969 |
| Cube | 9851265500453 |
| Square root | 146.413797 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 193 |
| Scientific notation | 2.1437 × |
21437 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and thirty-seven |
| Binary (base 2) | 101001110111101 |
| Octal (base 8) | 51675 |
| Hexadecimal (base 16) | 53BD |
| Base 3 | 1002101222 |
| As time | 21437 seconds = 5 h 57 min 17 s |
Is 21437 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 2) | 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 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | 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 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21437 a prime number?
No. 21437 = 13 × 17 × 97, so it is divisible by 13.
What are the factors of 21437?
1, 13, 17, 97, 221, 1261, 1649, 21437.
What is 21437 in binary?
101001110111101 (hexadecimal 53BD, octal 51675).
What is the square root of 21437?
About 146.4138.
Is 21437 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21437?
21437 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 17.