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Properties of the Number 6440

Six Thousand Four Hundred Forty

Basics

Value: 6439 → 6440 → 6441

Parity: even

Prime: No

Previous Prime: 6427

Next Prime: 6449

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 2 3 × 5 × 7 × 23

Divisors: 1, 2, 4, 5, 7, 8, 10, 14, 20, 23

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

4823 Try Today's Challenge

Representations

Binary: 1100100101000

Octal: 14450

Duodecimal: 3888

Hexadecimal: 1928

Square: 41473600

Square Root: 80.24961059095551

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

Rhombic matchstick numbers: a(n) = n*(3·n+2). A45944
a(n) = n*(4·n+1). A7742
Minimal (positive) solution a(n) of Pell equation b(n)2 - D(n)*a(n)2 = +4 with D(n)= A077425(n). The companion sequence is a(n)=A077428(n). A78355
Triangle T(n,k) of the number of strongly connected digraphs on n labeled nodes and with k arcs, k=0..n*(n-1). A57273
a(n) = 2·n*(4·n + 3). A33587
Triangle related to the asymptotic expansion of E(x,m=4,n). A163934
Numbers k such that k!!!! + 1 is prime. A85146
Perimeter of primitive integer-sided triangles with A < B < C < 2*π/3 and such that FA + FB + FC is an integer where F is the Fermat point of the triangle. A336333
Square array T(n,k) read by antidiagonals: coordination sequence for lattice Dn. A103903
Numbers k that divide the sum of digits of 13k. A175525