Properties of the Number 21078

Twenty-One Thousand Seventy-Eight

Basics

Value: 21077 → 21078 → 21079

Parity: even

Prime: No

Previous Prime: 21067

Next Prime: 21089

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 × 3 ² × 1171

Divisors: 1, 2, 3, 6, 9, 18, 1171, 2342, 3513, 7026

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001001010110

Octal: 51126

Duodecimal: 10246

Hexadecimal: 5256

Square: 444282084

Square Root: 145.18264359075434

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

Squares where knight moving to a lowest unvisited square on a spirally numbered board will have no available moves. A323714

a(n) = [x^n²] ∏_k=1..n ∑_m>=0 x^k·m². A321139

Number of regions formed in a hexagon by straight line segments when connecting the n-1 points between each corner that divide each edge into n equal parts to the n-1 points on the edge on the opposite side of the hexagon. A367662

p-INVERT of (1,0,0,0,1,0,0,0,0,0,...), where p(S) = (1 - S)². A292325

Positive integers k having no duplicated digit such that concatenating all successive absolute differences between two successive digits of k produces a divisor of k. A338641

Partial sums of A174928. A174929

Number of nX5 0..1 arrays with every element unequal to 0, 1, 3 or 4 king-move adjacent elements, with upper left element zero. A303805

a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = A000201 (lower Wythoff sequence). A24685

Interprimes which are of the form s·prime, s=18. A75293

Number of base 20 circular n-digit numbers with adjacent digits differing by 6 or less. A125408