256842 has 24 divisors (see below), whose sum is σ = 586560. Its totient is φ = 81000.

The previous prime is 256831. The next prime is 256873. The reversal of 256842 is 248652.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 256842.

It is an unprimeable number.

256842 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34 + ... + 717.

It is an arithmetic number, because the mean of its divisors is an integer number (24440).

2²⁵⁶⁸⁴² is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256842, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (293280).

256842 is an abundant number, since it is smaller than the sum of its proper divisors (329718).

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

256842 is a wasteful number, since it uses less digits than its factorization.

256842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778 (or 775 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 256842 is about 506.7958168730. The cubic root of 256842 is about 63.5655800464.

The spelling of 256842 in words is "two hundred fifty-six thousand, eight hundred forty-two".