| Base 10 | 639 (3 digits) | ||
| Digit Sum: 18 | Digital Root: 9 | sad | |
| Base 2 | 0b1001111111 (10 digits) | ||
| Digit Sum: 0b1000 | Digital Root: 0b1 | always happy | |
| Base 8 | 01177 (4 digits) | ||
| Digit Sum: 020 | Digital Root: 02 | sad | |
| Base 16 | 0x27f (3 digits) | ||
| Digit Sum: 0x18 | Digital Root: 0x9 | happy | |
More about this number at Positiv Integers and Number Empire.
The number is not a prime.
Its 3 (2 unique) factors are:
32 = 9
71
Its 6 divisors are:
1
3
9
71
213
639
Its aliquote sum is: 
297
makeing it a
deficient
number.
| In HTML this number represents this color: | 
 ⇧↑⇧↑⇧↑ #00027F ⇩↓⇩↓⇩↓  | 
As Unicode codepoint (since version 1.1) this number represents this character:ɿ LATIN SMALL LETTER REVERSED R WITH FISHHOOK in IPA_Ext (Source: https://www.unicode.org/Public/UCD/latest/ucdxml/ucd.all.grouped.zip); HTML: ɿ
In the work of Johann Sebastian Bach BWV 639 is Ich ruf zu dir, Herr Jesu Christ (à 2 Clav. et Ped.)
The number appears at position 531 of the decimal digits of π surrounded by
4406566430860213949463952247371907021798609 Source: The Pi-Search Page
Computations done with Math::BigInt 1.999811 and Math::Pari 2.030523 based on PARI/GP 2.11.3 (elapsed: 1104.402ms; cpu: 82.6509999999994ms)