678321 has 32 divisors (see below), whose sum is σ = 1191680. Its totient is φ = 373248.

The previous prime is 678299. The next prime is 678329. The reversal of 678321 is 123876.

678321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 678321 - 2⁵ = 678289 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

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

Its product of digits (2016) is a multiple of the sum of its prime divisors (144).

It is a Curzon number.

678321 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (678329) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6945 + ... + 7041.

It is an arithmetic number, because the mean of its divisors is an integer number (37240).

2⁶⁷⁸³²¹ is an apocalyptic number.

It is an amenable number.

678321 is a deficient number, since it is larger than the sum of its proper divisors (513359).

678321 is a wasteful number, since it uses less digits than its factorization.

678321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 144 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 678321 is about 823.6024526433. The cubic root of 678321 is about 87.8641585287.

It can be divided in two parts, 678 and 321, that added together give a palindrome (999).

The spelling of 678321 in words is "six hundred seventy-eight thousand, three hundred twenty-one".