820845 has 48 divisors (see below), whose sum is σ = 1600560. Its totient is φ = 387072.

The previous prime is 820837. The next prime is 820873. The reversal of 820845 is 548028.

820845 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 79524 + 741321 = 282^2 + 861^2 .

It is not a de Polignac number, because 820845 - 2³ = 820837 is a prime.

It is a zygodrome in base 3.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22167 + ... + 22203.

It is an arithmetic number, because the mean of its divisors is an integer number (33345).

2⁸²⁰⁸⁴⁵ is an apocalyptic number.

820845 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

820845 is a deficient number, since it is larger than the sum of its proper divisors (779715).

820845 is a wasteful number, since it uses less digits than its factorization.

820845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 27.

The square root of 820845 is about 906.0049668738. The cubic root of 820845 is about 93.6311560756.

The spelling of 820845 in words is "eight hundred twenty thousand, eight hundred forty-five".