The number 7770
7770 is a composite number with 32 divisors. Its prime factorisation is 2 × 3 × 5 × 7 × 37. Divisors (32): 1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 37, 42, 70, 74 … 7770.
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How to work it out
- 1
What is special about 7770: a Harshad number: divisible by its digit sum 21.
- 2
7770 is composite. Its prime factorisation is
- 3
The divisors add up to 21888; without 7770 itself that is 14118, so 7770 is abundant (14118 is more than 7770). Euler's totient φ(7770) = 1728 numbers up to 7770 share no factor with it.
- 4
The digits of 7770 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 39 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7770 = 2 \times 3 \times 5 \times 7 \times 37 \]
7770 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 21888 |
| Euler totient φ(n) | 1728 |
| Square | 60372900 |
| Cube | 469097433000 |
| Square root | 88.147603 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 39 |
| Scientific notation | 7.77 × |
7770 in other forms
| Form | Value |
|---|---|
| In words | seven thousand seven hundred and seventy |
| Binary (base 2) | 1111001011010 |
| Octal (base 8) | 17132 |
| Hexadecimal (base 16) | 1E5A |
| Base 3 | 101122210 |
| As time | 7770 seconds = 2 h 9 min 30 s |
Is 7770 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (7770 ÷ 2 = 3885) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (7770 ÷ 3 = 2590) | 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 (7770 ÷ 5 = 1554) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (7770 ÷ 6 = 1295) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (7770 ÷ 7 = 1110) | 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 (7770 ÷ 10 = 777) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 7770 a prime number?
No. 7770 = 2 × 3 × 5 × 7 × 37, so it is divisible by 2.
What are the factors of 7770?
1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 37, 42, 70, 74, 105, 111, 185, 210, 222, 259, 370, 518, 555, 777, 1110, 1295, 1554, 2590, 3885, 7770.
What is 7770 in binary?
1111001011010 (hexadecimal 1E5A, octal 17132).
What is the square root of 7770?
About 88.1476.
Is 7770 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 7770?
7770 is a Harshad number: divisible by its digit sum 21.