823840 has 48 divisors (see below), whose sum is σ = 2056320. Its totient is φ = 311040.

The previous prime is 823831. The next prime is 823841. The reversal of 823840 is 48328.

It is an Ulam number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (823841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2905 + ... + 3175.

It is an arithmetic number, because the mean of its divisors is an integer number (42840).

2⁸²³⁸⁴⁰ is an apocalyptic number.

823840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 823840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1028160).

823840 is an abundant number, since it is smaller than the sum of its proper divisors (1232480).

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

823840 is a wasteful number, since it uses less digits than its factorization.

823840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305 (or 297 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 823840 is about 907.6563226244. The cubic root of 823840 is about 93.7448945368.

The spelling of 823840 in words is "eight hundred twenty-three thousand, eight hundred forty".