The number 10121
10121 is a composite number with 4 divisors. Its prime factorisation is 29 × 349. Divisors (4): 1, 29, 349, 10121.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 10121: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 29 × 349, the product of two primes.
- 2
10121 is composite. Its prime factorisation is
- 3
The divisors add up to 10500; without 10121 itself that is 379, so 10121 is deficient (379 is less than 10121). Euler's totient φ(10121) = 9744 numbers up to 10121 share no factor with it.
- 4
The digits of 10121 add up to 5, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 179 steps to reach 1.
LaTeX source of the formulas on this page
\[ 10121 = 29 \times 349 \]
10121 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 10500 |
| Euler totient φ(n) | 9744 |
| Square | 102434641 |
| Cube | 1036741001561 |
| Square root | 100.603181 |
| Digit sum / digital root | 5 / 5 |
| Collatz steps to 1 | 179 |
| Scientific notation | 1.0121 × |
10121 in other forms
| Form | Value |
|---|---|
| In words | ten thousand one hundred and twenty-one |
| Binary (base 2) | 10011110001001 |
| Octal (base 8) | 23611 |
| Hexadecimal (base 16) | 2789 |
| Base 3 | 111212212 |
| As time | 10121 seconds = 2 h 48 min 41 s |
Is 10121 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | 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 10121 a prime number?
No. 10121 = 29 × 349, so it is divisible by 29.
What are the factors of 10121?
1, 29, 349, 10121.
What is 10121 in binary?
10011110001001 (hexadecimal 2789, octal 23611).
What is the square root of 10121?
About 100.6032.
Is 10121 divisible by 3?
No. Its digits add up to 5, which is not a multiple of 3.
What is special about the number 10121?
10121 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 29 × 349, the product of two primes.