The number 20101
20101 is the 2272nd prime number. Its only divisors are 1 and 20101.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20101: the 2272nd prime number.
- 2
20101 is prime, so its only factors are 1 and 20101. It is the 2272nd prime; the next prime is 20107 and the one before is 20089.
- 3
The divisors add up to 20102; without 20101 itself that is 1, so 20101 is deficient (1 is less than 20101). Euler's totient φ(20101) = 20100 numbers up to 20101 share no factor with it.
- 4
The digits of 20101 add up to 4, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 118 steps to reach 1.
20101 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 20102 |
| Euler totient φ(n) | 20100 |
| Square | 404050201 |
| Cube | 8121813090301 |
| Square root | 141.777995 |
| Digit sum / digital root | 4 / 4 |
| Collatz steps to 1 | 118 |
| Scientific notation | 2.0101 × |
20101 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand one hundred and one |
| Binary (base 2) | 100111010000101 |
| Octal (base 8) | 47205 |
| Hexadecimal (base 16) | 4E85 |
| Base 3 | 1000120111 |
| As time | 20101 seconds = 5 h 35 min 1 s |
Is 20101 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 4) | 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 4) | 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 20101 a prime number?
Yes. 20101 is divisible only by 1 and itself.
What are the factors of 20101?
1, 20101.
What is 20101 in binary?
100111010000101 (hexadecimal 4E85, octal 47205).
What is the square root of 20101?
About 141.7780.
Is 20101 divisible by 3?
No. Its digits add up to 4, which is not a multiple of 3.
What is special about the number 20101?
20101 is the 2272nd prime number.