815840 has 24 divisors (see below), whose sum is σ = 1927800. Its totient is φ = 326272.

The previous prime is 815831. The next prime is 815851. The reversal of 815840 is 48518.

It is a congruent number.

It is an unprimeable number.

815840 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, 2390 + ... + 2709.

It is an arithmetic number, because the mean of its divisors is an integer number (80325).

2⁸¹⁵⁸⁴⁰ is an apocalyptic number.

815840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

815840 is an abundant number, since it is smaller than the sum of its proper divisors (1111960).

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

815840 is a wasteful number, since it uses less digits than its factorization.

815840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5114 (or 5106 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 26.

The square root of 815840 is about 903.2386174207. The cubic root of 815840 is about 93.4404665486.

The spelling of 815840 in words is "eight hundred fifteen thousand, eight hundred forty".