678609 has 6 divisors (see below), whose sum is σ = 980226. Its totient is φ = 452400.

The previous prime is 678607. The next prime is 678611. The reversal of 678609 is 906876.

678609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (678607) and next prime (678611).

It can be written as a sum of positive squares in only one way, i.e., 540225 + 138384 = 735^2 + 372^2 .

It is not a de Polignac number, because 678609 - 2¹ = 678607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (678607) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 37692 + ... + 37709.

It is an arithmetic number, because the mean of its divisors is an integer number (163371).

2⁶⁷⁸⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

678609 is a deficient number, since it is larger than the sum of its proper divisors (301617).

678609 is a wasteful number, since it uses less digits than its factorization.

678609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75407 (or 75404 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 678609 is about 823.7772757245. Note that the first 3 decimals coincide. The cubic root of 678609 is about 87.8765918247.

The spelling of 678609 in words is "six hundred seventy-eight thousand, six hundred nine".