678985 has 8 divisors (see below), whose sum is σ = 819720. Its totient is φ = 539904.

The previous prime is 678971. The next prime is 678989. The reversal of 678985 is 589876.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 242064 + 436921 = 492^2 + 661^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 678985 - 2¹¹ = 676937 is a prime.

It is a super-2 number, since 2×678985² = 922041260450, which contains 22 as substring.

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

678985 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (678989) 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, 849 + ... + 1441.

It is an arithmetic number, because the mean of its divisors is an integer number (102465).

2⁶⁷⁸⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

678985 is a deficient number, since it is larger than the sum of its proper divisors (140735).

678985 is a wasteful number, since it uses less digits than its factorization.

678985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 827.

The product of its digits is 120960, while the sum is 43.

The square root of 678985 is about 824.0054611470. The cubic root of 678985 is about 87.8928188901.

The spelling of 678985 in words is "six hundred seventy-eight thousand, nine hundred eighty-five".