819980 has 24 divisors (see below), whose sum is σ = 1968288. Its totient is φ = 281088.

The previous prime is 819977. The next prime is 819989. The reversal of 819980 is 89918.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 819980.

It is not an unprimeable number, because it can be changed into a prime (819989) 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, 2789 + ... + 3068.

It is an arithmetic number, because the mean of its divisors is an integer number (82012).

2⁸¹⁹⁹⁸⁰ is an apocalyptic number.

It is an amenable number.

819980 is an abundant number, since it is smaller than the sum of its proper divisors (1148308).

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

819980 is a wasteful number, since it uses less digits than its factorization.

819980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5873 (or 5871 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 819980 is about 905.5274705938. The cubic root of 819980 is about 93.5982552576.

The spelling of 819980 in words is "eight hundred nineteen thousand, nine hundred eighty".