809720 has 32 divisors (see below), whose sum is σ = 1883520. Its totient is φ = 312960.

The previous prime is 809719. The next prime is 809729. The reversal of 809720 is 27908.

It is a self number, because there is not a number n which added to its sum of digits gives 809720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 914 + ... + 1566.

It is an arithmetic number, because the mean of its divisors is an integer number (58860).

2⁸⁰⁹⁷²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 809720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (941760).

809720 is an abundant number, since it is smaller than the sum of its proper divisors (1073800).

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

809720 is a wasteful number, since it uses less digits than its factorization.

809720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 695 (or 691 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 809720 is about 899.8444309990. The cubic root of 809720 is about 93.2062328901.

The spelling of 809720 in words is "eight hundred nine thousand, seven hundred twenty".