978
978 is the ISBN prefix that identifies a book.
- Even
- Composite
Where 978 fits
Why 978 is special
ISBNs were extended to thirteen digits in 2007 by prefixing 978, which made them valid EAN barcodes. A book's barcode and its identifier became the same number, which is why any scanner can read one.
Factors & digit properties
- Divisors (8)
- 1, 2, 3, 6, 163, 326, 489, 978
- Prime factorisation
- 2 × 3 × 163
- Digit sum
- 24
- Digital root
- 6
Representations
- Decimal
- 978
- Scientific notation
- 9.780 × 10^2
Roman numerals
C M L X X V I I I
CMLXXVIII uses the subtractive pair CM: a hundred before a thousand — a thousand minus a hundred.
Binary
1 1 1 1 0 1 0 0 1 0
1 × 512 + 1 × 256 + 1 × 128 + 1 × 64 + 0 × 32 + 1 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 0 × 1 = 978
Octal
1 7 2 2
1 × 512 + 7 × 64 + 2 × 8 + 2 × 1 = 978
Hexadecimal
3 d 2
3 × 256 + d × 16 + 2 × 1 = 978
Read as powers of two: 512 + 256 + 128 + 64 + 16 + 2 = 978.
In historical numeral systems
Egyptian
9 coils of rope, 7 hobbles, 8 strokes
9 × 100 + 7 × 10 + 8 × 1 = 978. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 corner wedge + 6 vertical wedges (sixties place), 1 corner wedge + 8 vertical wedges (units place)
16 × 60 + 18 = 978. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
sampi, then omicron, then eta, marked as a numeral
sampi-omicron-eta + keraia
sampi + omicron + eta written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
tav, then tav, then qof, then ayin, then het
tav-tav-qof-ayin-het
tav (400) + tav (400) + qof (100) + ayin (70) + het (8) = 978, written in descending order.
Systems that simply cannot reach this value are left out. Where a script needs a font most readers do not have, the reading is given instead of the glyphs — see number systems for each system in full.
Other mathematical patterns
- Abundant number
Related numbers & connections
978 and 979 are the two ISBN prefixes. Books issued under 979 have no ten-digit form at all, which quietly breaks systems that still assume one.
View 979 →Other connections
- is associated with979
why?
Strength 0.50, confidence "high".
Technology & computing
Prefixing 978 turned ten-digit ISBNs into thirteen-digit EAN codes in 2007, so book identifiers became ordinary retail barcodes. One change made every supermarket scanner able to read a book.
DocumentedTechnology & computingPeriod: 2007
Common questions
Is 978 a prime number?
No, 978 is not prime.
What are the factors of 978?
The factors of 978 are 1, 2, 3, 6, 163, 326, 489, 978.
What is 978 in Roman numerals?
978 in Roman numerals is CMLXXVIII. CM is subtractive: a hundred before a thousand — a thousand minus a hundred. Written additively it would be DCCCCLXXVIII, which Roman inscriptions used freely — the strict subtractive form is a later convention.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 15 July 2026