The number 802
802 is a composite number with 4 divisors. Its prime factorisation is 2 × 401. Divisors (4): 1, 2, 401, 802.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 802: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 2 × 401, the product of two primes.
- 2
802 is composite. Its prime factorisation is
- 3
The divisors add up to 1206; without 802 itself that is 404, so 802 is deficient (404 is less than 802). Euler's totient φ(802) = 400 numbers up to 802 share no factor with it.
- 4
The digits of 802 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 20 steps to reach 1.
LaTeX source of the formulas on this page
\[ 802 = 2 \times 401 \]
802 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1206 |
| Euler totient φ(n) | 400 |
| Square | 643204 |
| Cube | 515849608 |
| Square root | 28.319605 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 20 |
| Scientific notation | 8.02 × |
802 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and two |
| Roman numerals | DCCCII |
| Binary (base 2) | 1100100010 |
| Octal (base 8) | 1442 |
| Hexadecimal (base 16) | 322 |
| Base 3 | 1002201 |
| As time | 802 seconds = 13 min 22 s |
Is 802 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (802 ÷ 2 = 401) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | 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 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | 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 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 802 a prime number?
No. 802 = 2 × 401, so it is divisible by 2.
What are the factors of 802?
1, 2, 401, 802.
What is 802 in binary?
1100100010 (hexadecimal 322, octal 1442).
What is the square root of 802?
About 28.3196.
What is 802 in Roman numerals?
DCCCII.
Is 802 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 802?
802 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 2 × 401, the product of two primes.