The number 2421
2421 is a composite number with 6 divisors. Its prime factorisation is × 269. Divisors (6): 1, 3, 9, 269, 807, 2421.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2421: a Harshad number: divisible by its digit sum 9.
- 2
2421 is composite. Its prime factorisation is
- 3
The divisors add up to 3510; without 2421 itself that is 1089, so 2421 is deficient (1089 is less than 2421). Euler's totient φ(2421) = 1608 numbers up to 2421 share no factor with it.
- 4
The digits of 2421 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 19 steps to reach 1.
LaTeX source of the formulas on this page
\[ 2421 = 3^{2} \times 269 \]2421 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 3510 |
| Euler totient φ(n) | 1608 |
| Square | 5861241 |
| Cube | 14190064461 |
| Square root | 49.203658 (= 3√269) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 19 |
| Scientific notation | 2.421 × |
2421 in other forms
| Form | Value |
|---|---|
| In words | two thousand four hundred and twenty-one |
| Roman numerals | MMCDXXI |
| Binary (base 2) | 100101110101 |
| Octal (base 8) | 4565 |
| Hexadecimal (base 16) | 975 |
| Base 3 | 10022200 |
| As time | 2421 seconds = 40 min 21 s |
Is 2421 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 (2421 ÷ 3 = 807) | 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 | Yes (2421 ÷ 9 = 269) | 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 2421 a prime number?
No. 2421 = × 269, so it is divisible by 3.
What are the factors of 2421?
1, 3, 9, 269, 807, 2421.
What is 2421 in binary?
100101110101 (hexadecimal 975, octal 4565).
What is the square root of 2421?
About 49.2037, exactly 3√269.
What is 2421 in Roman numerals?
MMCDXXI.
Is 2421 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 2421?
2421 is a Harshad number: divisible by its digit sum 9.