55

This number is a composite.

55 is 5 times the 5^th prime. [Woods]

Every number greater than 55 is the sum of distinct primes of the form 4n + 3. [Wells]

If sigma(n)/n is greater than 9, then n has at least 55 distinct prime factors. [Laatsch]

Klimov (1975) showed that all integers are the sum of at most 55 prime numbers.

2^55-55 is the largest non-titanic prime of form 2^n-n, where n is a composite number. [Loungrides]