The Number
81
Eighty-One
In Base 8 Octal Is
1218
The numbers with a 8 subscript use Base 8 Octal notation.
For more familiar numbers: See Eighty-One in Base 10 Decimal
Nearby Numbers
Positive, nonzero integers within three units
Scientific Notation
Scientific notation expresses a quantity as the product of its significand with 10 raised to an integer exponent.
8.1e1
Reciprocal
A number multiplied with its reciprocal is one.
0.0062442607715335178
The reciprocal of 81 in Base 8 Octal.
Palindrome?
A numerical palindrome has the same value when all of its digits are reversed.
The number 1218 is a palindrome.
Not A Prime Number
A prime number is a positive integer that is divisible only by itself and one.
Eighty-one is a composite number with 5 total factors (including 1 and itself). See primes in Base 8 Octal
A Composite
Composites have more than just these two factors.
Eighty-one is a composite number with 5 total factors (including 1 and itself).
Prime Factors
The number eighty-one has the following 1 prime factor:
Prime Factorization
The prime factorization of a positive integer is the unique list of prime factors together with their multiplicities
384
= 1218
Base Conversions
The number eighty-one in 35 different bases