816816919978 has 16 divisors (see below), whose sum is σ = 1239235943040. Its totient is φ = 403740079776.

The previous prime is 816816919973. The next prime is 816816919979. The reversal of 816816919978 is 879919618618.

816816919978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 816816919978.

It is not an unprimeable number, because it can be changed into a prime (816816919973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 459775 + ... + 1358317.

It is an arithmetic number, because the mean of its divisors is an integer number (77452246440).

Almost surely, 2^816816919978 is an apocalyptic number.

816816919978 is a deficient number, since it is larger than the sum of its proper divisors (422419023062).

816816919978 is a wasteful number, since it uses less digits than its factorization.

816816919978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 903741.

The product of its digits is 94058496, while the sum is 73.

The spelling of 816816919978 in words is "eight hundred sixteen billion, eight hundred sixteen million, nine hundred nineteen thousand, nine hundred seventy-eight".