The number 1242
1242 is a composite number with 16 divisors. Its prime factorisation is 2 × × 23. Divisors (16): 1, 2, 3, 6, 9, 18, 23, 27, 46, 54, 69, 138, 207, 414, 621, 1242.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1242: a Harshad number: divisible by its digit sum 9.
- 2
1242 is composite. Its prime factorisation is
- 3
The divisors add up to 2880; without 1242 itself that is 1638, so 1242 is abundant (1638 is more than 1242). Euler's totient φ(1242) = 396 numbers up to 1242 share no factor with it.
- 4
The digits of 1242 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 88 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1242 = 2 \times 3^{3} \times 23 \]1242 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 2880 |
| Euler totient φ(n) | 396 |
| Square | 1542564 |
| Cube | 1915864488 |
| Square root | 35.242020 (= 3√138) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 88 |
| Scientific notation | 1.242 × |
1242 in other forms
| Form | Value |
|---|---|
| In words | one thousand two hundred and forty-two |
| Roman numerals | MCCXLII |
| Binary (base 2) | 10011011010 |
| Octal (base 8) | 2332 |
| Hexadecimal (base 16) | 4DA |
| Base 3 | 1201000 |
| As time | 1242 seconds = 20 min 42 s |
Is 1242 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1242 ÷ 2 = 621) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (1242 ÷ 3 = 414) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (1242 ÷ 6 = 207) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (1242 ÷ 9 = 138) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1242 a prime number?
No. 1242 = 2 × × 23, so it is divisible by 2.
What are the factors of 1242?
1, 2, 3, 6, 9, 18, 23, 27, 46, 54, 69, 138, 207, 414, 621, 1242.
What is 1242 in binary?
10011011010 (hexadecimal 4DA, octal 2332).
What is the square root of 1242?
About 35.2420, exactly 3√138.
What is 1242 in Roman numerals?
MCCXLII.
Is 1242 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 1242?
1242 is a Harshad number: divisible by its digit sum 9.