819978 has 16 divisors (see below), whose sum is σ = 1736640. Its totient is φ = 257216.

The previous prime is 819977. The next prime is 819989. The reversal of 819978 is 879918.

It is not an unprimeable number, because it can be changed into a prime (819977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3918 + ... + 4121.

It is an arithmetic number, because the mean of its divisors is an integer number (108540).

2⁸¹⁹⁹⁷⁸ is an apocalyptic number.

819978 is an abundant number, since it is smaller than the sum of its proper divisors (916662).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

819978 is a wasteful number, since it uses less digits than its factorization.

819978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8061.

The product of its digits is 36288, while the sum is 42.

The square root of 819978 is about 905.5263662644. The cubic root of 819978 is about 93.5981791596.

The spelling of 819978 in words is "eight hundred nineteen thousand, nine hundred seventy-eight".