257

The isotope -257 is the heaviest that can be formed by from naturally occuring .
The number 257 is also a OEIS, Sequence A000215 (accessed 2020-11-19) \(2^{2^3}+1\).
==Sources==
Category:Numbers
Category:Class 1
Category:Numbers in science
Category:Prime numbers
Category:Unnamed numbers
Category:Unnamed numbers with 3 digits