805840 has 40 divisors (see below), whose sum is σ = 2142720. Its totient is φ = 276096.

The previous prime is 805811. The next prime is 805843. The reversal of 805840 is 48508.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (805843) by changing a digit.

805840 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 7 ways as a sum of consecutive naturals, for example, 160 + ... + 1279.

It is an arithmetic number, because the mean of its divisors is an integer number (53568).

2⁸⁰⁵⁸⁴⁰ is an apocalyptic number.

805840 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 805840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1071360).

805840 is an abundant number, since it is smaller than the sum of its proper divisors (1336880).

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

805840 is a wasteful number, since it uses less digits than its factorization.

805840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1459 (or 1453 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 25.

The square root of 805840 is about 897.6859138919. The cubic root of 805840 is about 93.0571198800.

Subtracting from 805840 its sum of digits (25), we obtain a triangular number (805815 = T₁₂₆₉).

The spelling of 805840 in words is "eight hundred five thousand, eight hundred forty".