320656 has 30 divisors (see below), whose sum is σ = 724470. Its totient is φ = 137088.

The previous prime is 320647. The next prime is 320657. The reversal of 320656 is 656023.

It can be written as a sum of positive squares in only one way, i.e., 313600 + 7056 = 560^2 + 84^2 .

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (320657) by changing a digit.

320656 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 5 ways as a sum of consecutive naturals, for example, 580 + ... + 988.

It is an arithmetic number, because the mean of its divisors is an integer number (24149).

2³²⁰⁶⁵⁶ 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 320656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362235).

320656 is an abundant number, since it is smaller than the sum of its proper divisors (403814).

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

320656 is a wasteful number, since it uses less digits than its factorization.

320656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431 (or 418 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 320656 is about 566.2649556524. The cubic root of 320656 is about 68.4457453074.

Adding to 320656 its reverse (656023), we get a palindrome (976679).

The spelling of 320656 in words is "three hundred twenty thousand, six hundred fifty-six".