840891 has 4 divisors (see below), whose sum is σ = 1121192. Its totient is φ = 560592.

The previous prime is 840863. The next prime is 840907. The reversal of 840891 is 198048.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 840891 - 2⁵ = 840859 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (840821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140146 + ... + 140151.

It is an arithmetic number, because the mean of its divisors is an integer number (280298).

2⁸⁴⁰⁸⁹¹ is an apocalyptic number.

840891 is a deficient number, since it is larger than the sum of its proper divisors (280301).

840891 is a wasteful number, since it uses less digits than its factorization.

840891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280300.

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 840891 is about 917.0010905119. The cubic root of 840891 is about 94.3872286538.

The spelling of 840891 in words is "eight hundred forty thousand, eight hundred ninety-one".