Properties of the Number 1809

One Thousand Eight Hundred Nine

Basics

Value: 1808 → 1809 → 1810

Parity: odd

Prime: No

Previous Prime: 1801

Next Prime: 1811

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ³ × 67

Divisors: 1, 3, 9, 27, 67, 201, 603, 1809

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11100010001

Octal: 3421

Duodecimal: 1069

Hexadecimal: 711

Square: 3272481

Square Root: 42.532340636273474

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

Multiples of 9 containing a 9 in their decimal representation. A121029

Strictly superdiagonal compositions: compositions (p1, p2, p3, ...) of n such that π > i. A238874

a(n) = n*(5·n - 1)/2. A5476

Numbers m such that there are precisely 13 groups of order m. A292896

a(n) = n² + n + 3. A27688

a(n) = n*(5·n² - 3)/2. A63522

a(n) = 90·n - 81. A139280

a(1) = 1; a(n) is smallest number > a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime. A74336

Position of prime(n)# in A025487. A98719

a(n) = n*(11·n + 3)/2. A254963