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Properties of the Number 19640

Nineteen Thousand Six Hundred Forty

Basics

Value: 19639 → 19640 → 19641

Parity: even

Prime: No

Previous Prime: 19609

Next Prime: 19661

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 3 × 5 × 491

Divisors: 1, 2, 4, 5, 8, 10, 20, 40, 491, 982

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100110010111000

Octal: 46270

Duodecimal: B448

Hexadecimal: 4cb8

Square: 385729600

Square Root: 140.14278433083882

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 (undirected) cycles in the graph C3 X Pn. A339136
Alternating sum of the squares of the first n Fibonacci numbers with index divisible by 3. A156090
a(n) = 49·n2 + 2·n. A157365
Number of compositions of n with exactly seven occurrences of the largest part. A243742
Least term in period of continued fraction for sqrt(n) is 7. A31431
Solution to the Dancing School Problem with n girls and n+3 boys: f(n,3). A79922
Number of (n+4) X 10 0..1 matrices with each 5 X 5 subblock idempotent. A224688
Number of (n+1) X (1+1) 0..1 arrays with no element having a strict majority of its horizontal, vertical, diagonal and antidiagonal neighbors equal to one. A231799
Expansion of e.g.f. sec(log(1 + x)) + tan(log(1 + x)). A306336
a(n) is the least k such that a k-gon is the first polygon where an agreement of the areas of k-gons inscribed and circumscribed to a unit circle agree with the true value of π when truncated to n digits. A391013