Properties of the Number 20005

Twenty Thousand Five

Basics

Value: 20004 → 20005 → 20006

Parity: odd

Prime: No

Previous Prime: 19997

Next Prime: 20011

Digit Sum: 7

Digital Root: 7

Palindrome: No

Factorization: 5 × 4001

Divisors: 1, 5, 4001, 20005

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100111000100101

Octal: 47045

Duodecimal: B6B1

Hexadecimal: 4e25

Square: 400200025

Square Root: 141.4390328021229

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

List the positions of all digits '1' in the sequence. This is the lexicographically earliest increasing sequence with this property. A98645

Numbers k such that k³ divides 14^k² + 1. A177814

Squarefree n such that the elliptic curve n·y² = x³ - x arising in the "congruent number" problem has rank 3. A62693

Members of 3-cycles of permutation A111273. A113701

First differences of A260443. A277197

Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 9. A31422

Primitive sliding numbers (excludes multiples of 10): totals, including repetitions, of sums r + s, r >= s, such that 1/r + 1/s = (r + s)/10^k for some k >= 0. A103184

Numbers k such that k and k² use only the digits 0, 2, 3, 4 and 5. A136882

Numbers k such that k and k² use only the digits 0, 2, 4 and 5. A136897

Numbers k such that k and k² use only the digits 0, 2, 4, 5 and 6. A136898