823540 has 12 divisors (see below), whose sum is σ = 1729476. Its totient is φ = 329408.

The previous prime is 823519. The next prime is 823541. The reversal of 823540 is 45328.

It can be written as a sum of positive squares in 2 ways, for example, as 252004 + 571536 = 502^2 + 756^2 .

It is a nialpdrome in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (823541) by changing a digit.

823540 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20569 + ... + 20608.

It is an arithmetic number, because the mean of its divisors is an integer number (144123).

823540 is a Friedman number, since it can be written as (5+2)^(8-4^0)-3, using all its digits and the basic arithmetic operations.

2⁸²³⁵⁴⁰ is an apocalyptic number.

It is an amenable number.

823540 is an abundant number, since it is smaller than the sum of its proper divisors (905936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

823540 is a wasteful number, since it uses less digits than its factorization.

823540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41186 (or 41184 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 823540 is about 907.4910467878. The cubic root of 823540 is about 93.7335141382.

Adding to 823540 its reverse (45328), we get a palindrome (868868).

The spelling of 823540 in words is "eight hundred twenty-three thousand, five hundred forty".