The number 1290
1290 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 5 × 43. Divisors (16): 1, 2, 3, 5, 6, 10, 15, 30, 43, 86, 129, 215, 258, 430, 645, 1290.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1290: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
1290 is composite. Its prime factorisation is
- 3
The divisors add up to 3168; without 1290 itself that is 1878, so 1290 is abundant (1878 is more than 1290). Euler's totient φ(1290) = 336 numbers up to 1290 share no factor with it.
- 4
The digits of 1290 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 101 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1290 = 2 \times 3 \times 5 \times 43 \]
1290 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 3168 |
| Euler totient φ(n) | 336 |
| Square | 1664100 |
| Cube | 2146689000 |
| Square root | 35.916570 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 101 |
| Scientific notation | 1.29 × |
1290 in other forms
| Form | Value |
|---|---|
| In words | one thousand two hundred and ninety |
| Roman numerals | MCCXC |
| Binary (base 2) | 10100001010 |
| Octal (base 8) | 2412 |
| Hexadecimal (base 16) | 50A |
| Base 3 | 1202210 |
| As time | 1290 seconds = 21 min 30 s |
Is 1290 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1290 ÷ 2 = 645) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (1290 ÷ 3 = 430) | 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 | Yes (1290 ÷ 5 = 258) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (1290 ÷ 6 = 215) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (1290 ÷ 10 = 129) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | 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 1290 a prime number?
No. 1290 = 2 × 3 × 5 × 43, so it is divisible by 2.
What are the factors of 1290?
1, 2, 3, 5, 6, 10, 15, 30, 43, 86, 129, 215, 258, 430, 645, 1290.
What is 1290 in binary?
10100001010 (hexadecimal 50A, octal 2412).
What is the square root of 1290?
About 35.9166.
What is 1290 in Roman numerals?
MCCXC.
Is 1290 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 1290?
1290 is a happy number: repeatedly adding the squares of its digits reaches 1.