810009 has 6 divisors (see below), whose sum is σ = 1170026. Its totient is φ = 540000.

The previous prime is 809993. The next prime is 810013. The reversal of 810009 is 900018.

It can be written as a sum of positive squares in only one way, i.e., 810000 + 9 = 900^2 + 3^2 .

It is not a de Polignac number, because 810009 - 2⁴ = 809993 is a prime.

It is a super-2 number, since 2×810009² = 1312229160162, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 809973 and 810000.

It is not an unprimeable number, because it can be changed into a prime (810049) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 44992 + ... + 45009.

2⁸¹⁰⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

810009 is a deficient number, since it is larger than the sum of its proper divisors (360017).

810009 is a wasteful number, since it uses less digits than its factorization.

810009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90007 (or 90004 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 810009 is about 900.0049999861. The cubic root of 810009 is about 93.2173204254.

Subtracting 810009 from its reverse (900018), we obtain a palindrome (90009).

It can be divided in two parts, 81000 and 9, that multiplied together give a cube (729000 = 90³).

The spelling of 810009 in words is "eight hundred ten thousand, nine".