The number 1240
1240 is a composite number with 16 divisors. Its prime factorisation is × 5 × 31. Divisors (16): 1, 2, 4, 5, 8, 10, 20, 31, 40, 62, 124, 155, 248, 310, 620, 1240.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
1240 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
1240 is composite. Its prime factorisation is
- 3
The divisors add up to 2880; without 1240 itself that is 1640, so 1240 is abundant (1640 is more than 1240). Euler's totient φ(1240) = 480 numbers up to 1240 share no factor with it.
- 4
The digits of 1240 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 88 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1240 = 2^{3} \times 5 \times 31 \]1240 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 2880 |
| Euler totient φ(n) | 480 |
| Square | 1537600 |
| Cube | 1906624000 |
| Square root | 35.213634 (= 2√310) |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 88 |
| Scientific notation | 1.24 × |
1240 in other forms
| Form | Value |
|---|---|
| In words | one thousand two hundred and forty |
| Roman numerals | MCCXL |
| Binary (base 2) | 10011011000 |
| Octal (base 8) | 2330 |
| Hexadecimal (base 16) | 4D8 |
| Base 3 | 1200221 |
| As time | 1240 seconds = 20 min 40 s |
Is 1240 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1240 ÷ 2 = 620) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (1240 ÷ 4 = 310) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (1240 ÷ 5 = 248) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 | Yes (1240 ÷ 8 = 155) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (1240 ÷ 10 = 124) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1240 a prime number?
No. 1240 = × 5 × 31, so it is divisible by 2.
What are the factors of 1240?
1, 2, 4, 5, 8, 10, 20, 31, 40, 62, 124, 155, 248, 310, 620, 1240.
What is 1240 in binary?
10011011000 (hexadecimal 4D8, octal 2330).
What is the square root of 1240?
About 35.2136, exactly 2√310.
What is 1240 in Roman numerals?
MCCXL.
Is 1240 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 1240?
It is a composite number with 16 divisors.