811021 has 8 divisors (see below), whose sum is σ = 842688. Its totient is φ = 780000.

The previous prime is 810989. The next prime is 811037. The reversal of 811021 is 120118.

811021 = 4² + 5² + ... + 134².

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 811021 - 2⁵ = 810989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 810992 and 811010.

It is a congruent number.

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

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5296 + ... + 5446.

It is an arithmetic number, because the mean of its divisors is an integer number (105336).

2⁸¹¹⁰²¹ is an apocalyptic number.

It is an amenable number.

811021 is a deficient number, since it is larger than the sum of its proper divisors (31667).

811021 is a wasteful number, since it uses less digits than its factorization.

811021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 811021 is about 900.5670435898. The cubic root of 811021 is about 93.2561252077.

Adding to 811021 its reverse (120118), we get a palindrome (931139).

The spelling of 811021 in words is "eight hundred eleven thousand, twenty-one".