Properties of the Number 16905

Sixteen Thousand Nine Hundred Five

Basics

Value: 16904 → 16905 → 16906

Parity: odd

Prime: No

Previous Prime: 16903

Next Prime: 16921

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 5 × 7 ² × 23

Divisors: 1, 3, 5, 7, 15, 21, 23, 35, 49, 69

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2730 Try Today's Challenge

Representations

Binary: 100001000001001

Octal: 41011

Duodecimal: 9949

Hexadecimal: 4209

Square: 285779025

Square Root: 130.01922934704697

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

Array T(n,k) read by antidiagonals: T(n,k) is the number of [n,k]-triangulations in the plane, n >= 0, k >= 0. A169808

7 times hexagonal numbers: a(n) = 7·n*(2·n-1). A195320

Numbers that can be written in exactly two different ways as s₁^x_1 + ... + s_t^x_t, with 1 < s₁ < ... < s_t and {s₁,..., s_t} = {x₁,..., x_t} for some t > 0. A386966

Number of unrooted triangulations of a pentagon with n internal nodes. A5501

Triangle read by rows: T(n,k) is the number of n-node connected unsensed planar maps with an external face and k triangular internal faces, n >= 3, 1 <= k <= 2·n - 5. A378103

Numbers k such that σ(k) = ψ(k) + τ(k)². A390296

Expansion of ∏_k>=1 (1 + x^k) * (1 + x^2·k) * (1 + x^3·k) * (1 + x^4·k) * (1 + x^5·k). A327047

Odd numbers k such that the number of 1's in binary representation of k equals ω(k), the number of distinct primes in the factorization of k. A71595

a(n) = 25·n² + 5. A158445

Triangular array read by rows: T(n,k) is the number of forests of rooted trees on n labeled nodes with exactly k isolated nodes; n>=0, 0<=k<=n. A219034