820871 has 4 divisors (see below), whose sum is σ = 822744. Its totient is φ = 819000.

The previous prime is 820837. The next prime is 820873. The reversal of 820871 is 178028.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820871 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 820871.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820873) 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, 116 + ... + 1286.

It is an arithmetic number, because the mean of its divisors is an integer number (205686).

2⁸²⁰⁸⁷¹ is an apocalyptic number.

820871 is a deficient number, since it is larger than the sum of its proper divisors (1873).

820871 is a wasteful number, since it uses less digits than its factorization.

820871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1872.

The product of its (nonzero) digits is 896, while the sum is 26.

The square root of 820871 is about 906.0193154674. The cubic root of 820871 is about 93.6321446441.

Adding to 820871 its reverse (178028), we get a palindrome (998899).

The spelling of 820871 in words is "eight hundred twenty thousand, eight hundred seventy-one".