Properties of the Number 21965

Twenty-One Thousand Nine Hundred Sixty-Five

Basics

Value: 21964 → 21965 → 21966

Parity: odd

Prime: No

Previous Prime: 21961

Next Prime: 21977

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 5 × 23 × 191

Divisors: 1, 5, 23, 115, 191, 955, 4393, 21965

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010111001101

Octal: 52715

Duodecimal: 10865

Hexadecimal: 55cd

Square: 482461225

Square Root: 148.20593780277497

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 series-reduced planted trees with n leaves. Also the number of essentially series series-parallel networks with n edges; also the number of essentially parallel series-parallel networks with n edges. A669

Number of series-reduced rooted trees whose leaves span an initial interval of positive integers with multiplicities the integer partition with Heinz number n. A316655

T(n,k)=Number of (n·k)Xk binary arrays with rows in nonincreasing order, n ones in every column and no more than 3 ones in any row. A188416

Triangle read by rows: T(n,m) = number of unlabeled cographs on n nodes with m connected components. A106240

a(n) = n*(n-3)*(n²-7·n+14)/8. A176145

a(n) = 76·n² + 1. A158767

Number of partitions of n containing at least one part m-9 if m is the largest part. A212549

Triangle read by rows: T(n,k) is the number of permutation graphs on n vertices with domination number k, with 1 <= k <= n. A320578

Number of trees by stability index. A3427

a(n) = (3·n+1)*(5·n+1). A144459