The Number

81991

Eighty-One Thousand Nine Hundred and Ninety-One

In Base 21 Unovigesimal Is

8hj721

The numbers with a 21 subscript use Base 21 Unovigesimal notation.

For more familiar numbers: See Eighty-One Thousand Nine Hundred and Ninety-One in Base 10 Decimal

Nearby Numbers

Positive, nonzero integers within three units

81988
8hj421
Eighty-One Thousand Nine Hundred and Eighty-Eight in Base 21 Unovigesimal
81989
8hj521
Eighty-One Thousand Nine Hundred and Eighty-Nine in Base 21 Unovigesimal
81990
8hj621
Eighty-One Thousand Nine Hundred and Ninety in Base 21 Unovigesimal
81992
8hj821
Eighty-One Thousand Nine Hundred and Ninety-Two in Base 21 Unovigesimal
81993
8hj921
Eighty-One Thousand Nine Hundred and Ninety-Three in Base 21 Unovigesimal
81994
8hja21
Eighty-One Thousand Nine Hundred and Ninety-Four in Base 21 Unovigesimal

Scientific Notation

Scientific notation expresses a quantity as the product of its significand with 10 raised to an integer exponent.

8.1991e4

Reciprocal

A number multiplied with its reciprocal is one.

0.00027h0j05jj8ce621

The reciprocal of 81991 in Base 21 Unovigesimal.

Palindrome?

A numerical palindrome has the same value when all of its digits are reversed.

The number 8hj721 is not a palindrome.

Not A Prime Number

A prime number is a positive integer that is divisible only by itself and one.

Eighty-one thousand nine hundred and ninety-one is a composite number with 16 total factors (including 1 and itself).   See primes in Base 21 Unovigesimal

A Composite

Composites have more than just these two factors.

Eighty-one thousand nine hundred and ninety-one is a composite number with 16 total factors (including 1 and itself).

Prime Factors

The prime factors of a positive integer are the integers that divide it exactly and are also prime.

The number eighty-one thousand nine hundred and ninety-one has the following 4 prime factors:

7
721
Seven in Base 21 Unovigesimal
13
d21
Thirteen in Base 21 Unovigesimal
17
h21
Seventeen in Base 21 Unovigesimal
53
2b21
Fifty-Three in Base 21 Unovigesimal

Prime Factorization

The prime factorization of a positive integer is the unique list of prime factors together with their multiplicities

7211 · d211 · h211 · 2b211 = 8hj721

Base Conversions

The number eighty-one thousand nine hundred and ninety-one in 35 different bases