The first three digits in the decimal expansion of the Euler-Mascheroni constant (gamma = 0.5772156649...). It is not yet known if the constant is a rational number, i.e., the ratio of two integers a/b. [Kulsha]
577 is one of only two prime numbers with squares of the form AABCBC. Can you find the other? [Axoy]
The number of isomers of the C60H3
Buckminsterfullerene soccerball-shaped molecule. [Beedassy]
Smallest prime Fermat near miss, namely z such that x^3 +
y^3 = z^3 - 1 (x less than y, y less than z). [Post]
The largest prime on the cover of Marcus du Sautoy's book "The Music of the Primes" (American Edition).
The larger of only two 3-digit primes that remain prime
when inserting one, two or three zeros between each digit,
i.e., 50707, 5007007, 500070007 are primes. The other such
prime is 131. [Loungrides]
There are 577 prime-digit primes (other than 577) less than a million. [Merickel]
A prime ruler can be purchased at Kyoto University for 577 yen.
(There are 4 curios for this number that have not yet been approved by an editor.)