Properties of the Number 21145

Twenty-One Thousand One Hundred Forty-Five

Basics

Value: 21144 → 21145 → 21146

Parity: odd

Prime: No

Previous Prime: 21143

Next Prime: 21149

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 5 × 4229

Divisors: 1, 5, 4229, 21145

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001010011001

Octal: 51231

Duodecimal: 102A1

Hexadecimal: 5299

Square: 447111025

Square Root: 145.41320435228707

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

T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically. A207918

Triangle of coefficients from fractional iteration of e^x - 1. A8826

Number of proper partitions of a set of n labeled elements. A8827

Triangle T(n,k) read by rows: T(n,k) = (k-1)*T(n-1,k) + (n-k+2)*T(n-1, k-1), with T(n,1)=1, for 1 <= k <= n, n >= 1. A157011

The order of the semigroup of orientation-preserving partial transformations on n elements. A289713

Numbers k such that the continued fraction for sqrt(k) has period 53. A20392

a(n) = ∑_i=1..n LookAndSay(i). A79664

Positive numbers y such that y² is of the form x²+(x+2401)² with integer x. A157247

Number of n X n 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically. A207913

Number of nX5 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically. A207915