177

This number is a composite.

177 is the sum of all primes taken alternatively from 2 to 47 (which is the (1 + 7 + 7)th prime). [Gupta]

1^1*3^3*5^5*9^9*63^63*177^177+2 is the largest non titanic prime of form 1^1*3^3*5^5*9^9*63^63*177^177*…* a(n-1)^a(n-1)*a(n)^a(n)+2 where the bases and exponents are odd numbers, a(n) and 1^1*3^3*5^5*…* a(n-1)^a(n-1)*a(n)^a(n)+2 are prime, a(n)>a(n-1), and a(n) is minimal. Note that the previous primes of this form are for n = 1, 3, 5, 9, 63. [Loungrides]

The smallest possible magic constant for a 3-by-3 prime magic square. [Luen]

An adult centipede can have up to 177 semiprime pairs of legs. [Orkin]