Convert 78 954 685 792 129 to a Signed Binary (Base 2)

How to convert 78 954 685 792 129(10), a signed base 10 integer number? How to write it as a signed binary code in base 2

What are the required steps to convert base 10 integer
number 78 954 685 792 129 to signed binary code (in base 2)?

  • A signed integer, written in base ten, or a decimal system number, is a number written using the digits 0 through 9 and the sign, which can be positive (+) or negative (-). If positive, the sign is usually not written. A number written in base two, or binary, is a number written using only the digits 0 and 1.

1. Divide the number repeatedly by 2:

Keep track of each remainder.

Stop when you get a quotient that is equal to zero.


  • division = quotient + remainder;
  • 78 954 685 792 129 ÷ 2 = 39 477 342 896 064 + 1;
  • 39 477 342 896 064 ÷ 2 = 19 738 671 448 032 + 0;
  • 19 738 671 448 032 ÷ 2 = 9 869 335 724 016 + 0;
  • 9 869 335 724 016 ÷ 2 = 4 934 667 862 008 + 0;
  • 4 934 667 862 008 ÷ 2 = 2 467 333 931 004 + 0;
  • 2 467 333 931 004 ÷ 2 = 1 233 666 965 502 + 0;
  • 1 233 666 965 502 ÷ 2 = 616 833 482 751 + 0;
  • 616 833 482 751 ÷ 2 = 308 416 741 375 + 1;
  • 308 416 741 375 ÷ 2 = 154 208 370 687 + 1;
  • 154 208 370 687 ÷ 2 = 77 104 185 343 + 1;
  • 77 104 185 343 ÷ 2 = 38 552 092 671 + 1;
  • 38 552 092 671 ÷ 2 = 19 276 046 335 + 1;
  • 19 276 046 335 ÷ 2 = 9 638 023 167 + 1;
  • 9 638 023 167 ÷ 2 = 4 819 011 583 + 1;
  • 4 819 011 583 ÷ 2 = 2 409 505 791 + 1;
  • 2 409 505 791 ÷ 2 = 1 204 752 895 + 1;
  • 1 204 752 895 ÷ 2 = 602 376 447 + 1;
  • 602 376 447 ÷ 2 = 301 188 223 + 1;
  • 301 188 223 ÷ 2 = 150 594 111 + 1;
  • 150 594 111 ÷ 2 = 75 297 055 + 1;
  • 75 297 055 ÷ 2 = 37 648 527 + 1;
  • 37 648 527 ÷ 2 = 18 824 263 + 1;
  • 18 824 263 ÷ 2 = 9 412 131 + 1;
  • 9 412 131 ÷ 2 = 4 706 065 + 1;
  • 4 706 065 ÷ 2 = 2 353 032 + 1;
  • 2 353 032 ÷ 2 = 1 176 516 + 0;
  • 1 176 516 ÷ 2 = 588 258 + 0;
  • 588 258 ÷ 2 = 294 129 + 0;
  • 294 129 ÷ 2 = 147 064 + 1;
  • 147 064 ÷ 2 = 73 532 + 0;
  • 73 532 ÷ 2 = 36 766 + 0;
  • 36 766 ÷ 2 = 18 383 + 0;
  • 18 383 ÷ 2 = 9 191 + 1;
  • 9 191 ÷ 2 = 4 595 + 1;
  • 4 595 ÷ 2 = 2 297 + 1;
  • 2 297 ÷ 2 = 1 148 + 1;
  • 1 148 ÷ 2 = 574 + 0;
  • 574 ÷ 2 = 287 + 0;
  • 287 ÷ 2 = 143 + 1;
  • 143 ÷ 2 = 71 + 1;
  • 71 ÷ 2 = 35 + 1;
  • 35 ÷ 2 = 17 + 1;
  • 17 ÷ 2 = 8 + 1;
  • 8 ÷ 2 = 4 + 0;
  • 4 ÷ 2 = 2 + 0;
  • 2 ÷ 2 = 1 + 0;
  • 1 ÷ 2 = 0 + 1;

2. Construct the base 2 representation of the positive number:

Take all the remainders starting from the bottom of the list constructed above.

78 954 685 792 129(10) = 100 0111 1100 1111 0001 0001 1111 1111 1111 1111 1000 0001(2)


3. Determine the signed binary number bit length:

  • The base 2 number's actual length, in bits: 47.

  • A signed binary's bit length must be equal to a power of 2, as of:
  • 21 = 2; 22 = 4; 23 = 8; 24 = 16; 25 = 32; 26 = 64; ...
  • The first bit (the leftmost) is reserved for the sign:
  • 0 = positive integer number, 1 = negative integer number

The least number that is:


1) a power of 2

2) and is larger than the actual length, 47,

3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)


=== is: 64.


4. Get the positive binary computer representation on 64 bits (8 Bytes):

If needed, add extra 0s in front (to the left) of the base 2 number, up to the required length, 64:


78 954 685 792 129(10) Base 10 integer number converted and written as a signed binary code (in base 2):

78 954 685 792 129(10) = 0000 0000 0000 0000 0100 0111 1100 1111 0001 0001 1111 1111 1111 1111 1000 0001

Spaces were used to group digits: for binary, by 4, for decimal, by 3.

How to convert signed base 10 integers in decimal to binary code system

Follow the steps below to convert a signed base ten integer number to signed binary:

  • 1. In a signed binary, first bit (the leftmost) is reserved for sign: 0 = positive integer number, 1 = positive integer number. If the number to be converted is negative, start with its positive version.
  • 2. Divide repeatedly by 2 the positive integer number keeping track of each remainder. STOP when we get a quotient that is ZERO.
  • 3. Construct the base 2 representation of the positive number, by taking all the remainders starting from the bottom of the list constructed above. Thus, the last remainder of the divisions becomes the first symbol (the leftmost) of the base two number, while the first remainder becomes the last symbol (the rightmost).
  • 4. Binary numbers represented in computer language have a length of 4, 8, 16, 32, 64, ... bits (power of 2) - if needed, fill in extra '0' bits in front of the base 2 number (to the left), up to the right length; this way the first bit (the leftmost one) is always '0', as for a positive representation.
  • 5. To get the negative reprezentation of the number, simply switch the first bit (the leftmost one), from '0' to '1'.

Example: convert the negative number -63 from decimal system (base ten) to signed binary code system:

  • 1. Start with the positive version of the number: |-63| = 63;
  • 2. Divide repeatedly 63 by 2, keeping track of each remainder, until we get a quotient that is equal to zero:
    • division = quotient + remainder
    • 63 ÷ 2 = 31 + 1
    • 31 ÷ 2 = 15 + 1
    • 15 ÷ 2 = 7 + 1
    • 7 ÷ 2 = 3 + 1
    • 3 ÷ 2 = 1 + 1
    • 1 ÷ 2 = 0 + 1
  • 3. Construct the base 2 representation of the positive number, by taking all the remainders starting from the bottom of the list constructed above:
    63(10) = 11 1111(2)
  • 4. The actual length of base 2 representation number is 6, so the positive binary computer representation length of the signed binary will take in this case 8 bits (the least power of 2 higher than 6) - add extra '0's in front (to the left), up to the required length; this way the first bit (the leftmost one) is to be '0', as for a positive number:
    63(10) = 0011 1111(2)
  • 5. To get the negative integer number representation simply change the first bit (the leftmost), from '0' to '1':
    -63(10) = 1011 1111
  • Number -63(10), signed integer, converted from decimal system (base 10) to signed binary = 1011 1111