The number 21137
21137 is a composite number with 4 divisors. Its prime factorisation is 23 × 919. Divisors (4): 1, 23, 919, 21137.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21137: a semiprime: 23 × 919, the product of two primes.
- 2
21137 is composite. Its prime factorisation is
- 3
The divisors add up to 22080; without 21137 itself that is 943, so 21137 is deficient (943 is less than 21137). Euler's totient φ(21137) = 20196 numbers up to 21137 share no factor with it.
- 4
The digits of 21137 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21137 = 23 \times 919 \]
21137 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 22080 |
| Euler totient φ(n) | 20196 |
| Square | 446772769 |
| Cube | 9443436018353 |
| Square root | 145.385694 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1137 × |
21137 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and thirty-seven |
| Binary (base 2) | 101001010010001 |
| Octal (base 8) | 51221 |
| Hexadecimal (base 16) | 5291 |
| Base 3 | 1001222212 |
| As time | 21137 seconds = 5 h 52 min 17 s |
Is 21137 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 4) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | 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 6) | 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 21137 a prime number?
No. 21137 = 23 × 919, so it is divisible by 23.
What are the factors of 21137?
1, 23, 919, 21137.
What is 21137 in binary?
101001010010001 (hexadecimal 5291, octal 51221).
What is the square root of 21137?
About 145.3857.
Is 21137 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 21137?
21137 is a semiprime: 23 × 919, the product of two primes.