778197979917 has 48 divisors (see below), whose sum is σ = 1177265232000. Its totient is φ = 494413476480.

The previous prime is 778197979891. The next prime is 778197979927. The reversal of 778197979917 is 719979791877.

It is a happy number.

It is not a de Polignac number, because 778197979917 - 2⁸ = 778197979661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (778197979927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 83233959 + ... + 83243307.

It is an arithmetic number, because the mean of its divisors is an integer number (24526359000).

Almost surely, 2^778197979917 is an apocalyptic number.

It is an amenable number.

778197979917 is a deficient number, since it is larger than the sum of its proper divisors (399067252083).

778197979917 is a wasteful number, since it uses less digits than its factorization.

778197979917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10818 (or 10815 counting only the distinct ones).

The product of its digits is 882165816, while the sum is 81.

The spelling of 778197979917 in words is "seven hundred seventy-eight billion, one hundred ninety-seven million, nine hundred seventy-nine thousand, nine hundred seventeen".