778381917953 has 2 divisors, whose sum is σ = 778381917954. Its totient is φ = 778381917952.

The previous prime is 778381917947. The next prime is 778381918003. The reversal of 778381917953 is 359719183877.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 687809811649 + 90572106304 = 829343^2 + 300952^2 .

It is a cyclic number.

It is not a de Polignac number, because 778381917953 - 2⁸ = 778381917697 is a prime.

It is not a weakly prime, because it can be changed into another prime (778381917923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 389190958976 + 389190958977.

It is an arithmetic number, because the mean of its divisors is an integer number (389190958977).

Almost surely, 2^778381917953 is an apocalyptic number.

It is an amenable number.

778381917953 is a deficient number, since it is larger than the sum of its proper divisors (1).

778381917953 is an equidigital number, since it uses as much as digits as its factorization.

778381917953 is an evil number, because the sum of its binary digits is even.

The product of its digits is 80015040, while the sum is 68.

The spelling of 778381917953 in words is "seven hundred seventy-eight billion, three hundred eighty-one million, nine hundred seventeen thousand, nine hundred fifty-three".