This number is a prime.
The largest three-digit prime which remains prime when 2 is added to any of its digits, i.e., 547, 367, and 349, are primes. [Opao]
Strobogrammatic primes on a calculator do not contain the digits 3, 4, or 7.
The fictitional street number of Dracula's London house (347 Piccadilly) according to Leslie S. Klinger's book The New Annotated Dracula. [Post]
There are exactly 347 even digits before the 347th odd digit of π. (347 is the smallest prime making the previous statement true.) [Keith]
(347, 743) is the first pair of emirps (p, q) such that 5^p and 5^q are both "apocalyptic numbers", i.e., numbers that contain the beast number. [Loungrides]
2^2*3^3*7^7*347^347-1 is the largest non-titanic prime of form 2^2*3^3*7^7*347^347*...* a(n-1)^a(n-1)*a(n)^a(n)-1, where n, a(n) and 2^2*3^3*...*a(n)^a(n) – 1 are prime, a(n)>a(n-1), and a(n) is minimal. Note that the previous such primes are: a(1) = 2^2-1 = 3, a(2) = 2^2*3^3-1 = 107, a(3) = 2^2*3^3*7^7*-1 = 88942643. [Loungrides]
Shula's 347 Grill serves up prime cuts in a contemporary setting with sports photos on the walls.
On November 24, 2018, Yusheng Du (杜宇生) broke the world record fastest time to solve a 3x3 Rubik's cube. He solved it in 3.47 seconds. [Apdos]
The only emirp that can be represented as the number of lines in a Rhapsody of Homer’s Odyssey, (i.e. Rhapsody VΙI). This line says: «πὰρ δὲ γυνὴ δέσποινα λέχος πόρσυνε καὶ εὐνήν». [Loungrides]