820851 has 4 divisors (see below), whose sum is σ = 1094472. Its totient is φ = 547232.

The previous prime is 820837. The next prime is 820873. The reversal of 820851 is 158028.

820851 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 820851 - 2⁷ = 820723 is a prime.

It is a D-number.

It is a plaindrome in base 15.

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 3 ways as a sum of consecutive naturals, for example, 136806 + ... + 136811.

It is an arithmetic number, because the mean of its divisors is an integer number (273618).

2⁸²⁰⁸⁵¹ is an apocalyptic number.

820851 is a deficient number, since it is larger than the sum of its proper divisors (273621).

820851 is a wasteful number, since it uses less digits than its factorization.

820851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273620.

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 820851 is about 906.0082781079. The cubic root of 820851 is about 93.6313842087.

Adding to 820851 its reverse (158028), we get a palindrome (978879).

The spelling of 820851 in words is "eight hundred twenty thousand, eight hundred fifty-one".