The number 20901
20901 is a composite number with 4 divisors. Its prime factorisation is 3 × 6967. Divisors (4): 1, 3, 6967, 20901.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20901: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 6967, the product of two primes.
- 2
20901 is composite. Its prime factorisation is
- 3
The divisors add up to 27872; without 20901 itself that is 6971, so 20901 is deficient (6971 is less than 20901). Euler's totient φ(20901) = 13932 numbers up to 20901 share no factor with it.
- 4
The digits of 20901 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 87 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20901 = 3 \times 6967 \]
20901 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 27872 |
| Euler totient φ(n) | 13932 |
| Square | 436851801 |
| Cube | 9130639492701 |
| Square root | 144.571781 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 87 |
| Scientific notation | 2.0901 × |
20901 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand nine hundred and one |
| Binary (base 2) | 101000110100101 |
| Octal (base 8) | 50645 |
| Hexadecimal (base 16) | 51A5 |
| Base 3 | 1001200010 |
| As time | 20901 seconds = 5 h 48 min 21 s |
Is 20901 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 | Yes (20901 ÷ 3 = 6967) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 3) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20901 a prime number?
No. 20901 = 3 × 6967, so it is divisible by 3.
What are the factors of 20901?
1, 3, 6967, 20901.
What is 20901 in binary?
101000110100101 (hexadecimal 51A5, octal 50645).
What is the square root of 20901?
About 144.5718.
Is 20901 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 20901?
20901 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 6967, the product of two primes.