842805 has 20 divisors (see below), whose sum is σ = 1511532. Its totient is φ = 449280.

The previous prime is 842801. The next prime is 842813. The reversal of 842805 is 508248.

It can be written as a sum of positive squares in 2 ways, for example, as 311364 + 531441 = 558^2 + 729^2 .

It is not a de Polignac number, because 842805 - 2² = 842801 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a plaindrome in base 12.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 842805.

It is not an unprimeable number, because it can be changed into a prime (842801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 636 + ... + 1445.

2⁸⁴²⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

842805 is a deficient number, since it is larger than the sum of its proper divisors (668727).

842805 is a wasteful number, since it uses less digits than its factorization.

842805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2098 (or 2089 counting only the distinct ones).

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

The square root of 842805 is about 918.0441165870. The cubic root of 842805 is about 94.4587877741.

The spelling of 842805 in words is "eight hundred forty-two thousand, eight hundred five".