The number 21149
21149 is the 2377th prime number. Its only divisors are 1 and 21149.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21149: the 2377th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
21149 is prime, so its only factors are 1 and 21149. It is the 2377th prime; the next prime is 21157 and the one before is 21143.
- 3
The divisors add up to 21150; without 21149 itself that is 1, so 21149 is deficient (1 is less than 21149). Euler's totient φ(21149) = 21148 numbers up to 21149 share no factor with it.
- 4
The digits of 21149 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 79 steps to reach 1.
21149 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 21150 |
| Euler totient φ(n) | 21148 |
| Square | 447280201 |
| Cube | 9459528970949 |
| Square root | 145.426958 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 79 |
| Scientific notation | 2.1149 × |
21149 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and forty-nine |
| Binary (base 2) | 101001010011101 |
| Octal (base 8) | 51235 |
| Hexadecimal (base 16) | 529D |
| Base 3 | 1002000022 |
| As time | 21149 seconds = 5 h 52 min 29 s |
Is 21149 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 4) | 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 2) | 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 9) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21149 a prime number?
Yes. 21149 is divisible only by 1 and itself.
What are the factors of 21149?
1, 21149.
What is 21149 in binary?
101001010011101 (hexadecimal 529D, octal 51235).
What is the square root of 21149?
About 145.4270.
Is 21149 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21149?
21149 is the 2377th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.