Properties of the Number 1105

One Thousand One Hundred Five

Basics

Value: 1104 → 1105 → 1106

Parity: odd

Prime: No

Previous Prime: 1103

Next Prime: 1109

Digit Sum: 7

Digital Root: 7

Palindrome: No

Factorization: 5 × 13 × 17

Divisors: 1, 5, 13, 17, 65, 85, 221, 1105

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10001010001

Octal: 2121

Duodecimal: 781

Hexadecimal: 451

Square: 1221025

Square Root: 33.24154027718932

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

Moser-de Bruijn sequence: sums of distinct powers of 4. A695

Fermat pseudoprimes to base 2, also called Sarrus numbers or Poulet numbers. A1567

Carmichael numbers: composite numbers k such that a^k-1 == 1 (mod k) for every a coprime to k. A2997

Centered square numbers: a(n) = 2·n*(n+1)+1. Sums of two consecutive squares. Also, consider all Pythagorean triples (X, Y, Z=Y+1) ordered by increasing Z; then sequence gives Z values. A1844

a(n) = n*(n² + 1)/2. A6003

10-gonal (or decagonal) numbers: a(n) = n*(4·n-3). A1107

a(n) = ceiling(n²/2). A982

Y-toothpick sequence (see Comments lines for definition). A160120

Generalized 10-gonal numbers: m*(4·m - 3) for m = 0, +- 1, +- 2, +- 3, ... A74377

Expansion of ∏_m>=1 (1 + m·q^m). A22629