858840 has 64 divisors (see below), whose sum is σ = 2734560. Its totient is φ = 215040.

The previous prime is 858833. The next prime is 858841. The reversal of 858840 is 48858.

858840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×858840² = 1475212291200, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 858840.

It is not an unprimeable number, because it can be changed into a prime (858841) by changing a digit.

858840 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 15 ways as a sum of consecutive naturals, for example, 1830 + ... + 2250.

2⁸⁵⁸⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 858840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1367280).

858840 is an abundant number, since it is smaller than the sum of its proper divisors (1875720).

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

858840 is a wasteful number, since it uses less digits than its factorization.

858840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452 (or 448 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 33.

The square root of 858840 is about 926.7362084218. The cubic root of 858840 is about 95.0540781671.

The spelling of 858840 in words is "eight hundred fifty-eight thousand, eight hundred forty".