103 is the natural number following 102 and preceding 104.

List of numbers — Integers << 100 101 102 103 104 105 106 107 108 109 >>
Cardinal	one hundred [and] three
Ordinal	103rd (one hundred [and] third)
Factorization	prime
Roman numeral	CIII
Binary	1100111
Hexadecimal	67

One hundred three is the 27th prime number. The previous prime is 101, making them both twin primes.

One hundred three is also:

• The atomic number of lawrencium, an actinide.
• The flight number of Pan Am Flight 103, which crashed over Lockerbie, Scottland and was at one time called "the air-disaster of the century".
• The year AD 103 or 103 BC.