285 (number)
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| ||||
|---|---|---|---|---|
| Cardinal | two hundred eighty-five | |||
| Ordinal | 285th (two hundred eighty-fifth) | |||
| Factorization | 3 × 5 × 19 | |||
| Divisors | 1, 3, 5, 15, 19, 57, 95, 285 | |||
| Greek numeral | ΣΠΕ´ | |||
| Roman numeral | CCLXXXV, cclxxxv | |||
| Binary | 1000111012 | |||
| Ternary | 1011203 | |||
| Senary | 11536 | |||
| Octal | 4358 | |||
| Duodecimal | 1B912 | |||
| Hexadecimal | 11D16 | |||
285 is the natural number following 284 and preceding 286.
In mathematics
[edit]- 285 is an odd composite number.[1]
- 285 is the 9th square pyramidal number. That means it is the sum of a number of consecutive perfect squares starting with 1. For 285, it is the sum of all of the single digits' perfect squares.[2]
- 285 is the number of variations possible with a binary rooted tree with 13 points. A binary rooted tree means that it always begins with 1 point that is rooted. From there, each point can branch in up to two directions.[3]
- 285 is a sphenic number which means that it has three prime factors.[4]
- 285 is a Harshad number. That means that it is divisible by the sum of its digits. 285 is divisible by 15.[5]
- 285 is a repdigit number in base 7. In base 7, 285 is 555.[6]
- 285 is a very symmetric number. If flipped horizontally, these numbers are symmetrical.[7]
References
[edit]- ^ "Composite numbers". mathworld.wolfram.com.
- ^ "Square pyramidal number sequence". marhworld.wolfram.com.
- ^ "Binary rooted tree". mathworld.wolfram.com.
- ^ "Sphenic numbers". mathworld.wolfram.com.
- ^ "Harshad numbers". mathworld.wolfram.com.
- ^ "Repdigit numbers". mathworld.wolfram.com.
- ^ Sloane, N. J. A. (ed.). "Sequence A053701 (Vertically symmetric numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.