Properties of the Number 81920

Eighty-One Thousand Nine Hundred Twenty

Basics

Value: 81919 → 81920 → 81921

Parity: even

Prime: No

Previous Prime: 81919

Next Prime: 81929

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 ¹⁴ × 5

Divisors: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10100000000000000

Octal: 240000

Duodecimal: 3B4A8

Hexadecimal: 14000

Square: 6710886400

Square Root: 286.2167011199731

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: Yes

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

Expansion of (1+x)/(1-4·x). A3947

a(n) = 5·2ⁿ. A20714

Triangle read by rows. T(n, m) are the coefficients of Sidi polynomials. A75513

Numbers of the form 2^k times 1, 3 or 5. A29747

a(n) is the maximal number of a's that can be produced in a blank document with n "keystrokes". A193286

15-almost primes (generalization of semiprimes). A69276

Triangle read by rows: coefficients T(n,k) of a binomial decomposition of nⁿ as Sum(k=0..n)T(n,k)*binomial(n,k). A244120

Consider the Post tag system defined in A284116; a(n) = number of binary words of length n which terminate at the empty word. A289670

Numbers of the form 2^k or 5·2^k. A94958

Binary expansion is 1x100...0 where x = 0 or 1. A70875