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Properties of the Number 21642

Twenty-One Thousand Six Hundred Forty-Two

Basics

Value: 21641 → 21642 → 21643

Parity: even

Prime: No

Previous Prime: 21617

Next Prime: 21647

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 2 × 3 × 3607

Divisors: 1, 2, 3, 6, 3607, 7214, 10821, 21642

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010010001010

Octal: 52212

Duodecimal: 10636

Hexadecimal: 548a

Square: 468376164

Square Root: 147.11220207719006

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

Number of compositions of n whose run-lengths are all different. A329739
T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 1, 2, 3, 5 or 8 king-move adjacent elements, with upper left element zero. A299345
Numbers n with property that for each single digit d of n, we can also see the decimal expansion of 2d as a substring of n. Also n may not contain any zero digits. A135016
Number of (w,x,y,z) with all terms in {0,...,n} and |w-x|=max{w,x,y,z}-min{w,x,y,z}. A212755
Triangle read by rows: T(0,0) = 1; T(n,k) = T(n-1, k) + 2·T(n-1, k-1) + 3·T(n-1, k-2) + 4·T(n-1, k-3) + 5·T(n-1, k-4) + 6·T(n-1, k-5) for k = 0..5·n; T(n,k)=0 for n or k < 0. A319092
A factorial-Pascal matrix. A162747
Number of nX3 0..1 arrays with every element equal to 0, 1, 2, 3, 5 or 8 king-move adjacent elements, with upper left element zero. A299340
Number of nX7 0..1 arrays with every element equal to 0, 1, 2, 3, 5 or 8 king-move adjacent elements, with upper left element zero. A299344
Integer part of the area of circles with prime radii. A97427
a(n) = |{0 < k <= n: the number of twin prime pairs not exceeding k·n is a square}|. A237840