The number 1220
1220 is a composite number with 12 divisors. Its prime factorisation is × 5 × 61. Divisors (12): 1, 2, 4, 5, 10, 20, 61, 122, 244, 305, 610, 1220.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1220: a Harshad number: divisible by its digit sum 5.
- 2
1220 is composite. Its prime factorisation is
- 3
The divisors add up to 2604; without 1220 itself that is 1384, so 1220 is abundant (1384 is more than 1220). Euler's totient φ(1220) = 480 numbers up to 1220 share no factor with it.
- 4
The digits of 1220 add up to 5, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 39 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1220 = 2^{2} \times 5 \times 61 \]1220 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 2604 |
| Euler totient φ(n) | 480 |
| Square | 1488400 |
| Cube | 1815848000 |
| Square root | 34.928498 (= 2√305) |
| Digit sum / digital root | 5 / 5 |
| Collatz steps to 1 | 39 |
| Scientific notation | 1.22 × |
1220 in other forms
| Form | Value |
|---|---|
| In words | one thousand two hundred and twenty |
| Roman numerals | MCCXX |
| Binary (base 2) | 10011000100 |
| Octal (base 8) | 2304 |
| Hexadecimal (base 16) | 4C4 |
| Base 3 | 1200012 |
| As time | 1220 seconds = 20 min 20 s |
Is 1220 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1220 ÷ 2 = 610) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (1220 ÷ 4 = 305) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (1220 ÷ 5 = 244) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (1220 ÷ 10 = 122) | 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 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1220 a prime number?
No. 1220 = × 5 × 61, so it is divisible by 2.
What are the factors of 1220?
1, 2, 4, 5, 10, 20, 61, 122, 244, 305, 610, 1220.
What is 1220 in binary?
10011000100 (hexadecimal 4C4, octal 2304).
What is the square root of 1220?
About 34.9285, exactly 2√305.
What is 1220 in Roman numerals?
MCCXX.
Is 1220 divisible by 3?
No. Its digits add up to 5, which is not a multiple of 3.
What is special about the number 1220?
1220 is a Harshad number: divisible by its digit sum 5.