678509 has 16 divisors (see below), whose sum is σ = 799680. Its totient is φ = 570240.

The previous prime is 678499. The next prime is 678533. The reversal of 678509 is 905876.

It is a cyclic number.

It is not a de Polignac number, because 678509 - 2⁴ = 678493 is a prime.

It is an Ulam number.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (678599) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10094 + ... + 10160.

It is an arithmetic number, because the mean of its divisors is an integer number (49980).

2⁶⁷⁸⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

678509 is a deficient number, since it is larger than the sum of its proper divisors (121171).

678509 is a wasteful number, since it uses less digits than its factorization.

678509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 678509 is about 823.7165774707. The cubic root of 678509 is about 87.8722751068.

The spelling of 678509 in words is "six hundred seventy-eight thousand, five hundred nine".