321856 has 28 divisors (see below), whose sum is σ = 658368. Its totient is φ = 156032.

The previous prime is 321851. The next prime is 321889. The reversal of 321856 is 658123.

It is a happy number.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 321856.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321851) by changing a digit.

321856 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 (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2955 + ... + 3061.

2³²¹⁸⁵⁶ 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 321856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (329184).

321856 is an abundant number, since it is smaller than the sum of its proper divisors (336512).

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

321856 is a wasteful number, since it uses less digits than its factorization.

321856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166 (or 156 counting only the distinct ones).

The product of its digits is 1440, while the sum is 25.

The square root of 321856 is about 567.3235408477. The cubic root of 321856 is about 68.5310211672.

Adding to 321856 its reverse (658123), we get a palindrome (979979).

The spelling of 321856 in words is "three hundred twenty-one thousand, eight hundred fifty-six".