Properties of the Number 280

Two Hundred Eighty

Basics

Value: 279 → 280 → 281

Parity: even

Prime: No

Previous Prime: 277

Next Prime: 281

Digit Sum: 10

Digital Root: 1

Palindrome: No

Factorization: 2 ³ × 5 × 7

Divisors: 1, 2, 4, 5, 7, 8, 10, 14, 20, 28

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100011000

Octal: 430

Duodecimal: 1B4

Hexadecimal: 118

Square: 78400

Square Root: 16.73320053068151

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

a(n) = denominator of harmonic number H(n) = ∑_i=1..n 1/i. A2805

Octagonal numbers: n*(3·n-2). Also called star numbers. A567

Numbers whose base-3 representation contains no 2. A5836

a(n) is the number of partitions of n into at most 3 parts; also partitions of n+3 in which the greatest part is 3; also number of unlabeled multigraphs with 3 nodes and n edges. A1399

Triangle T(n,k) 0<=k<n : Number of compositions of n with k adjacent equal parts. A106356

Numbers k such that k² + 1 is prime. A5574

Numbers that are the sum of 2 positive cubes. A3325

Triple factorial numbers (3·n-2)!!! with leading 1 added. A7559

Generalized octagonal numbers: k*(3·k-2), k=0, +- 1, +- 2, +-3, ... A1082

Numbers that contain a digit 0. A11540