The Number

1981

One Thousand Nine Hundred and Eighty-One

In Base 21 Unovigesimal Is

4a721

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

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

Nearby Numbers

Positive, nonzero integers within three units

1978
4a421
One Thousand Nine Hundred and Seventy-Eight in Base 21 Unovigesimal
1979
4a521
One Thousand Nine Hundred and Seventy-Nine in Base 21 Unovigesimal
1980
4a621
One Thousand Nine Hundred and Eighty in Base 21 Unovigesimal
1982
4a821
One Thousand Nine Hundred and Eighty-Two in Base 21 Unovigesimal
1983
4a921
One Thousand Nine Hundred and Eighty-Three in Base 21 Unovigesimal
1984
4aa21
One Thousand Nine Hundred and Eighty-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.

1.981e3

Reciprocal

A number multiplied with its reciprocal is one.

0.004e3d7a838e6fd21

The reciprocal of 1981 in Base 21 Unovigesimal.

Palindrome?

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

The number 4a721 is not a palindrome.

Not A Prime Number

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

One thousand nine hundred and eighty-one is a composite number with 4 total factors (including 1 and itself).   See primes in Base 21 Unovigesimal

A Composite

Composites have more than just these two factors.

One thousand nine hundred and eighty-one is a composite number with 4 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 one thousand nine hundred and eighty-one has the following 2 prime factors:

7
721
Seven in Base 21 Unovigesimal
283
da21
Two Hundred and Eighty-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 · da211 = 4a721

Base Conversions

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