810081 has 20 divisors (see below), whose sum is σ = 1235652. Its totient is φ = 528768.

The previous prime is 810079. The next prime is 810091. The reversal of 810081 is 180018.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 467856 + 342225 = 684^2 + 585^2 .

It is not a de Polignac number, because 810081 - 2¹ = 810079 is a prime.

It is a super-2 number, since 2×810081² = 1312462453122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810071) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 5845 + ... + 5981.

2⁸¹⁰⁰⁸¹ is an apocalyptic number.

810081 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

810081 is a deficient number, since it is larger than the sum of its proper divisors (425571).

810081 is a wasteful number, since it uses less digits than its factorization.

810081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222 (or 213 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 810081 is about 900.0449988751. The cubic root of 810081 is about 93.2200823076.

Adding to 810081 its reverse (180018), we get a palindrome (990099).

It can be divided in two parts, 8100 and 81, that multiplied together give a square (656100 = 810²).

The spelling of 810081 in words is "eight hundred ten thousand, eighty-one".