Number 81

Interestingness: 13 · Rank #58 of 1000

Visual representations

Binary image (n×n bits)
Element Tl – Thallium
Heptagonal · P7(6) = 81
Square · P4(9) = 81
3⁴
Prime factorization

Representations of 81

Greek numeral
παʹ
Sanskrit numeral
८१
Arabic numeral
٨١
Roman numeral
LXXXI
Maya numeral
●●●●
●
Chinese numeral
八十一
Hebrew numeral
פא
Egyptian numeral
𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
𓏹
Morse code
---...----

81 in different numeral systems

Binary
1010001
Base-3
10000
Base-4
1101
Base-5
311
Base-6
213
Base-7
144
Base-8
121
Duodecimal
69
Hex
51
Vigesimal
41
Base-24
39
Base-36
29
Negabinary
1010001

Factorization

Prime factors: 3
Divisors: 1, 3, 9, 27, 81
Sum of divisors other than 81: 40
Product of prime factors: 81 = 3 × 3 × 3 × 3

Number-theory characteristics (10)

Heptagonal Square Fourth Power Perfect Power Difference of 2 squares Odious number Powerful number Odd Composite Deficient

Base-10 digit properties (1)

These depend on the decimal representation of the number.

Harshad

Related primes

Number 81 prime
Prime number before 81
Prime number after 81