It is a weak prime.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-50778205401509 is a prime.
It is a congruent number.
Almost surely, 250778205401509 is an apocalyptic number.
It is an amenable number.
50778205401509 is an equidigital number, since it uses as much as digits as its factorization.
50778205401509 is an evil number, because the sum of its binary digits is even.
The spelling of 50778205401509 in words is "fifty trillion, seven hundred seventy-eight billion, two hundred five million, four hundred one thousand, five hundred nine".