Properties of the Number 20745

Twenty Thousand Seven Hundred Forty-Five

Basics

Value: 20744 → 20745 → 20746

Parity: odd

Prime: No

Previous Prime: 20743

Next Prime: 20747

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 5 × 461

Divisors: 1, 3, 5, 9, 15, 45, 461, 1383, 2305, 4149

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000100001001

Octal: 50411

Duodecimal: 10009

Hexadecimal: 5109

Square: 430355025

Square Root: 144.03124660989366

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

a(n) = a(n-2) + a(n-3) + a(n-4) - a(n-6), with a(0) = a(2) = a(3) = 1, a(1) = 0 and a(4) = a(5) = 2. A143438

Expansion of 4th power of continued fraction 1/ ( 1+q/ ( 1+q²/ ( 1+q³/ ( 1+q⁴/... )))). A55103

Numbers k such that 2·k+1, 4·k+1, 8·k+1 and 16·k+1 are primes. A124412

Numbers k such that 2k+1, 4k+1, 6k+1 and 8k+1 are primes. A124409

Determinant of n X n Hankel matrix whose entries are t(i+j), 0 <= i, j < n, where t is the Thue-Morse sequence. A56887

a(n) = 81·n² + 9. A157888

Norm of coefficients in the expansion of 1 / (1 - x - 2·I*x²), where I²=-1. A218135

Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 32. A31710

Integer quotients π(m·prime(m))/m. A84298

Coefficients in the series (1 + x - x⁴ - x⁶ - x⁸ - x⁹ - x¹⁰ - x¹² - x¹⁴ ...)/(1 - x² - x³ - x⁵ - x⁷ - x¹¹ - x¹³ ...). A58354