The number 3240
3240 is a triangular number: 1 + 2 + … + 80 = 3240. Its prime factorisation is × × 5. Divisors (40): 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 27, 30 … 3240.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 3240: a triangular number: 1 + 2 + … + 80 = 3240; a Harshad number: divisible by its digit sum 9.
- 2
3240 is composite. Its prime factorisation is
- 3
The divisors add up to 10890; without 3240 itself that is 7650, so 3240 is abundant (7650 is more than 3240). Euler's totient φ(3240) = 864 numbers up to 3240 share no factor with it.
- 4
The digits of 3240 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 30 steps to reach 1.
LaTeX source of the formulas on this page
\[ 3240 = 2^{3} \times 3^{4} \times 5 \]3240 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 40 |
| Sum of divisors | 10890 |
| Euler totient φ(n) | 864 |
| Square | 10497600 |
| Cube | 34012224000 |
| Square root | 56.920998 (= 18√10) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 30 |
| Scientific notation | 3.24 × |
3240 in other forms
| Form | Value |
|---|---|
| In words | three thousand two hundred and forty |
| Roman numerals | MMMCCXL |
| Binary (base 2) | 110010101000 |
| Octal (base 8) | 6250 |
| Hexadecimal (base 16) | CA8 |
| Base 3 | 11110000 |
| As time | 3240 seconds = 54 min 0 s |
Is 3240 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (3240 ÷ 2 = 1620) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (3240 ÷ 3 = 1080) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (3240 ÷ 4 = 810) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (3240 ÷ 5 = 648) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (3240 ÷ 6 = 540) | 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 | Yes (3240 ÷ 8 = 405) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (3240 ÷ 9 = 360) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (3240 ÷ 10 = 324) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (3240 ÷ 12 = 270) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 3240 a prime number?
No. 3240 = × × 5, so it is divisible by 2.
What are the factors of 3240?
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 27, 30, 36, 40, 45, 54, 60, 72, 81, 90, 108, 120, 135, 162, 180, 216, 270, 324, 360, 405, 540, 648, 810, 1080, 1620, 3240.
What is 3240 in binary?
110010101000 (hexadecimal CA8, octal 6250).
What is the square root of 3240?
About 56.9210, exactly 18√10.
What is 3240 in Roman numerals?
MMMCCXL.
Is 3240 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 3240?
3240 is a triangular number: 1 + 2 + … + 80 = 3240; a Harshad number: divisible by its digit sum 9.