The number 20401
20401 is a composite number with 4 divisors. Its prime factorisation is 23 × 887. Divisors (4): 1, 23, 887, 20401.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20401: a semiprime: 23 × 887, the product of two primes.
- 2
20401 is composite. Its prime factorisation is
- 3
The divisors add up to 21312; without 20401 itself that is 911, so 20401 is deficient (911 is less than 20401). Euler's totient φ(20401) = 19492 numbers up to 20401 share no factor with it.
- 4
The digits of 20401 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 43 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20401 = 23 \times 887 \]
20401 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 21312 |
| Euler totient φ(n) | 19492 |
| Square | 416200801 |
| Cube | 8490912541201 |
| Square root | 142.832069 |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 43 |
| Scientific notation | 2.0401 × |
20401 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand four hundred and one |
| Binary (base 2) | 100111110110001 |
| Octal (base 8) | 47661 |
| Hexadecimal (base 16) | 4FB1 |
| Base 3 | 1000222121 |
| As time | 20401 seconds = 5 h 40 min 1 s |
Is 20401 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 3) | 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 7) | 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 7) | 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 20401 a prime number?
No. 20401 = 23 × 887, so it is divisible by 23.
What are the factors of 20401?
1, 23, 887, 20401.
What is 20401 in binary?
100111110110001 (hexadecimal 4FB1, octal 47661).
What is the square root of 20401?
About 142.8321.
Is 20401 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 20401?
20401 is a semiprime: 23 × 887, the product of two primes.