The number 801
801 is a composite number with 6 divisors. Its prime factorisation is × 89. Divisors (6): 1, 3, 9, 89, 267, 801.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 801: a Harshad number: divisible by its digit sum 9.
- 2
801 is composite. Its prime factorisation is
- 3
The divisors add up to 1170; without 801 itself that is 369, so 801 is deficient (369 is less than 801). Euler's totient φ(801) = 528 numbers up to 801 share no factor with it.
- 4
The digits of 801 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 59 steps to reach 1.
LaTeX source of the formulas on this page
\[ 801 = 3^{2} \times 89 \]801 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 1170 |
| Euler totient φ(n) | 528 |
| Square | 641601 |
| Cube | 513922401 |
| Square root | 28.301943 (= 3√89) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 59 |
| Scientific notation | 8.01 × |
801 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and one |
| Roman numerals | DCCCI |
| Binary (base 2) | 1100100001 |
| Octal (base 8) | 1441 |
| Hexadecimal (base 16) | 321 |
| Base 3 | 1002200 |
| As time | 801 seconds = 13 min 21 s |
Is 801 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (801 ÷ 3 = 267) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (801 ÷ 9 = 89) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 801 a prime number?
No. 801 = × 89, so it is divisible by 3.
What are the factors of 801?
1, 3, 9, 89, 267, 801.
What is 801 in binary?
1100100001 (hexadecimal 321, octal 1441).
What is the square root of 801?
About 28.3019, exactly 3√89.
What is 801 in Roman numerals?
DCCCI.
Is 801 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 801?
801 is a Harshad number: divisible by its digit sum 9.