The number 26821
26821 is the 2942nd prime number. Its only divisors are 1 and 26821.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 26821: the 2942nd prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
26821 is prime, so its only factors are 1 and 26821. It is the 2942nd prime; the next prime is 26833 and the one before is 26813.
- 3
The divisors add up to 26822; without 26821 itself that is 1, so 26821 is deficient (1 is less than 26821). Euler's totient φ(26821) = 26820 numbers up to 26821 share no factor with it.
- 4
The digits of 26821 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 46 steps to reach 1.
26821 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 26822 |
| Euler totient φ(n) | 26820 |
| Square | 719366041 |
| Cube | 19294116585661 |
| Square root | 163.771182 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 46 |
| Scientific notation | 2.6821 × |
26821 in other forms
| Form | Value |
|---|---|
| In words | twenty-six thousand eight hundred and twenty-one |
| Binary (base 2) | 110100011000101 |
| Octal (base 8) | 64305 |
| Hexadecimal (base 16) | 68C5 |
| Base 3 | 1100210101 |
| As time | 26821 seconds = 7 h 27 min 1 s |
Is 26821 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 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | 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 | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 26821 a prime number?
Yes. 26821 is divisible only by 1 and itself.
What are the factors of 26821?
1, 26821.
What is 26821 in binary?
110100011000101 (hexadecimal 68C5, octal 64305).
What is the square root of 26821?
About 163.7712.
Is 26821 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 26821?
26821 is the 2942nd prime number; a happy number: repeatedly adding the squares of its digits reaches 1.