320840 has 32 divisors (see below), whose sum is σ = 778680. Its totient is φ = 118272.

The previous prime is 320839. The next prime is 320843. The reversal of 320840 is 48023.

320840 = 71² + 72² + ... + 109².

It can be written as a sum of positive squares in 4 ways, for example, as 103684 + 217156 = 322^2 + 466^2 .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 320840.

It is not an unprimeable number, because it can be changed into a prime (320843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 212 + ... + 828.

2³²⁰⁸⁴⁰ 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 320840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (389340).

320840 is an abundant number, since it is smaller than the sum of its proper divisors (457840).

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

320840 is a wasteful number, since it uses less digits than its factorization.

320840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 641 (or 637 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 320840 is about 566.4274004672. The cubic root of 320840 is about 68.4588347334.

Adding to 320840 its reverse (48023), we get a palindrome (368863).

The spelling of 320840 in words is "three hundred twenty thousand, eight hundred forty".