809819 has 8 divisors (see below), whose sum is σ = 852720. Its totient is φ = 768096.

The previous prime is 809803. The next prime is 809821. The reversal of 809819 is 918908.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 809819 - 2⁴ = 809803 is a prime.

It is a super-2 number, since 2×809819² = 1311613625522, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809839) 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, 1337 + ... + 1845.

It is an arithmetic number, because the mean of its divisors is an integer number (106590).

2⁸⁰⁹⁸¹⁹ is an apocalyptic number.

809819 is a deficient number, since it is larger than the sum of its proper divisors (42901).

809819 is a wasteful number, since it uses less digits than its factorization.

809819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 589.

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

The square root of 809819 is about 899.8994388264. The cubic root of 809819 is about 93.2100313394.

The spelling of 809819 in words is "eight hundred nine thousand, eight hundred nineteen".