A large number or the largest number are terms that may refer to:

• Large numbers, for notations to exactly specify very large numbers
• Names of large numbers, for the largest numbers with names

In mathematics and physics

• Infinity, a concept which can be used as a largest number in some contexts
• Graham's number, once claimed as the largest number ever used in a serious mathematical proof
• Largest known prime number, for the largest known primes
• Dirac large numbers hypothesis, for cosmology.

In computing

• Arbitrary-precision arithmetic
• The constant 127, 32767, 2147483647, or 9223372036854775807, in a byte, a word of 16, 32, or 64 bits in two's-complement format
• The constant 255, 65535, 4294967295, or 18446744073709551615, in a byte, a word of 16, 32, or 64 bits with no sign bit
• The constant 3.4028235e+38 or 1.7976931348623157e+308, in a word of 32 or 64 bits using the binary IEEE 754-2008 floating-point representation

See also

• Infinitesimal (smallest number)
• Integer (computer science)#Common integral data types - ranges of common integer data types