816784108978 has 16 divisors (see below), whose sum is σ = 1233037205784. Its totient is φ = 405771949440.

The previous prime is 816784108957. The next prime is 816784108979. The reversal of 816784108978 is 879801487618.

It can be written as a sum of positive squares in 4 ways, for example, as 552683704329 + 264100404649 = 743427^2 + 513907^2 .

It is not an unprimeable number, because it can be changed into a prime (816784108979) 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 7 ways as a sum of consecutive naturals, for example, 8726926 + ... + 8820022.

Almost surely, 2^816784108978 is an apocalyptic number.

816784108978 is a deficient number, since it is larger than the sum of its proper divisors (416253096806).

816784108978 is a wasteful number, since it uses less digits than its factorization.

816784108978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121197.

The product of its (nonzero) digits is 43352064, while the sum is 67.

The spelling of 816784108978 in words is "eight hundred sixteen billion, seven hundred eighty-four million, one hundred eight thousand, nine hundred seventy-eight".