Is a megabyte larger than a gigabyte

No, it isn't. Check this table below:

1 byte = 8 bits

1 Kilobyte = 1,000 bytes (in SI)

1 Megabyte = 1,000,000 bytes (in SI)

1 Gigabyte = 1,000,000,000 bytes (in SI)

1 Terabyte = 1,000,000,000,000 bytes (in SI)

1 Petabyte = 1,000,000,000,000,000 bytes (in SI)

1 Kilobyte = 1,024 bytes (in binary)

1 Megabyte = 1,048,576 bytes (in binary)

1 Gigabyte = 1,073,741,824 bytes (in binary)

1 Terabyte = 1,099,511,627,776 bytes (in binary)

1 Petabyte = 1,125,899,906,842,624 bytes (in binary)

So, as you can see 1 Megabyte is equal to 1,000,000 bytes, and 1 Gigabyte is equal to 1,000,000,000 bytes in the decimal system. There is also a binary system that computers use. In binary (or base 2), 1 megabyte consists of 1,048,576 bytes, and 1 gigabyte consists of 1,073,741,824 bytes. In other words, 1 Megabyte is equivalent to 0.001 gigabytes in base 10, and 0.0009765625 gigabytes in base two. 

We can finally say that a gigabyte is one thousand times bigger than a megabyte.