820811 has 8 divisors (see below), whose sum is σ = 886464. Its totient is φ = 757120.

The previous prime is 820793. The next prime is 820837. The reversal of 820811 is 118028.

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 820811 - 2⁶ = 820747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820891) 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, 446 + ... + 1356.

It is an arithmetic number, because the mean of its divisors is an integer number (110808).

2⁸²⁰⁸¹¹ is an apocalyptic number.

820811 is a deficient number, since it is larger than the sum of its proper divisors (65653).

820811 is a wasteful number, since it uses less digits than its factorization.

820811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 981.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 820811 is about 905.9862029855. The cubic root of 820811 is about 93.6298633008.

Adding to 820811 its reverse (118028), we get a palindrome (938839).

The spelling of 820811 in words is "eight hundred twenty thousand, eight hundred eleven".