855840 has 48 divisors (see below), whose sum is σ = 2697408. Its totient is φ = 228096.

The previous prime is 855821. The next prime is 855851. The reversal of 855840 is 48558.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 855798 and 855807.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 412 + ... + 1371.

It is an arithmetic number, because the mean of its divisors is an integer number (56196).

2⁸⁵⁵⁸⁴⁰ is an apocalyptic number.

855840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

855840 is an abundant number, since it is smaller than the sum of its proper divisors (1841568).

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

855840 is a wasteful number, since it uses less digits than its factorization.

855840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1801 (or 1793 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 30.

The square root of 855840 is about 925.1162089165. The cubic root of 855840 is about 94.9432717646.

The spelling of 855840 in words is "eight hundred fifty-five thousand, eight hundred forty".