The number 42921
42921 is a composite number with 12 divisors. Its prime factorisation is × 19 × 251. Divisors (12): 1, 3, 9, 19, 57, 171, 251, 753, 2259, 4769, 14307, 42921.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42921 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42921 is composite. Its prime factorisation is
- 3
The divisors add up to 65520; without 42921 itself that is 22599, so 42921 is deficient (22599 is less than 42921). Euler's totient φ(42921) = 27000 numbers up to 42921 share no factor with it.
- 4
The digits of 42921 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 150 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42921 = 3^{2} \times 19 \times 251 \]42921 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 65520 |
| Euler totient φ(n) | 27000 |
| Square | 1842212241 |
| Cube | 79069591595961 |
| Square root | 207.173840 (= 3√4769) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 150 |
| Scientific notation | 4.2921 × |
42921 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand nine hundred and twenty-one |
| Binary (base 2) | 1010011110101001 |
| Octal (base 8) | 123651 |
| Hexadecimal (base 16) | A7A9 |
| Base 3 | 2011212200 |
| As time | 42921 seconds = 11 h 55 min 21 s |
Is 42921 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 (42921 ÷ 3 = 14307) | 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (42921 ÷ 9 = 4769) | 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 10) | 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 42921 a prime number?
No. 42921 = × 19 × 251, so it is divisible by 3.
What are the factors of 42921?
1, 3, 9, 19, 57, 171, 251, 753, 2259, 4769, 14307, 42921.
What is 42921 in binary?
1010011110101001 (hexadecimal A7A9, octal 123651).
What is the square root of 42921?
About 207.1738, exactly 3√4769.
Is 42921 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 42921?
It is a composite number with 12 divisors.