The number 19801
19801 is the 2241st prime number and a binary palindrome (100110101011001). Its only divisors are 1 and 19801.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 19801: the 2241st prime number; a binary palindrome (100110101011001).
- 2
19801 is prime, so its only factors are 1 and 19801. It is the 2241st prime; the next prime is 19813 and the one before is 19793.
- 3
The divisors add up to 19802; without 19801 itself that is 1, so 19801 is deficient (1 is less than 19801). Euler's totient φ(19801) = 19800 numbers up to 19801 share no factor with it.
- 4
The digits of 19801 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 136 steps to reach 1.
19801 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 19802 |
| Euler totient φ(n) | 19800 |
| Square | 392079601 |
| Cube | 7763568179401 |
| Square root | 140.716026 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 136 |
| Scientific notation | 1.9801 × |
19801 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand eight hundred and one |
| Binary (base 2) | 100110101011001 |
| Octal (base 8) | 46531 |
| Hexadecimal (base 16) | 4D59 |
| Base 3 | 1000011101 |
| As time | 19801 seconds = 5 h 30 min 1 s |
Is 19801 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 5) | 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 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 1) | 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 19801 a prime number?
Yes. 19801 is divisible only by 1 and itself.
What are the factors of 19801?
1, 19801.
What is 19801 in binary?
100110101011001 (hexadecimal 4D59, octal 46531).
What is the square root of 19801?
About 140.7160.
Is 19801 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 19801?
19801 is the 2241st prime number; a binary palindrome (100110101011001).