The number 15401
15401 is the 1800th prime number. Its only divisors are 1 and 15401.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 15401: the 1800th prime number.
- 2
15401 is prime, so its only factors are 1 and 15401. It is the 1800th prime; the next prime is 15413 and the one before is 15391.
- 3
The divisors add up to 15402; without 15401 itself that is 1, so 15401 is deficient (1 is less than 15401). Euler's totient φ(15401) = 15400 numbers up to 15401 share no factor with it.
- 4
The digits of 15401 add up to 11, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 146 steps to reach 1.
15401 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 15402 |
| Euler totient φ(n) | 15400 |
| Square | 237190801 |
| Cube | 3652975526201 |
| Square root | 124.100766 |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 146 |
| Scientific notation | 1.5401 × |
15401 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand four hundred and one |
| Binary (base 2) | 11110000101001 |
| Octal (base 8) | 36051 |
| Hexadecimal (base 16) | 3C29 |
| Base 3 | 210010102 |
| As time | 15401 seconds = 4 h 16 min 41 s |
Is 15401 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 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 2) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 15401 a prime number?
Yes. 15401 is divisible only by 1 and itself.
What are the factors of 15401?
1, 15401.
What is 15401 in binary?
11110000101001 (hexadecimal 3C29, octal 36051).
What is the square root of 15401?
About 124.1008.
Is 15401 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 15401?
15401 is the 1800th prime number.