811001 has 4 divisors (see below), whose sum is σ = 818292. Its totient is φ = 803712.

The previous prime is 810989. The next prime is 811037. The reversal of 811001 is 100118.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 354025 + 456976 = 595^2 + 676^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-811001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (811081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3476 + ... + 3701.

It is an arithmetic number, because the mean of its divisors is an integer number (204573).

2⁸¹¹⁰⁰¹ is an apocalyptic number.

It is an amenable number.

811001 is a deficient number, since it is larger than the sum of its proper divisors (7291).

811001 is a wasteful number, since it uses less digits than its factorization.

811001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7290.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 811001 is about 900.5559394063. Note that the first 3 decimals coincide. The cubic root of 811001 is about 93.2553586275.

Adding to 811001 its reverse (100118), we get a palindrome (911119).

The spelling of 811001 in words is "eight hundred eleven thousand, one".