678561 has 16 divisors (see below), whose sum is σ = 989184. Its totient is φ = 411264.

The previous prime is 678553. The next prime is 678563. The reversal of 678561 is 165876.

It is not a de Polignac number, because 678561 - 2³ = 678553 is a prime.

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

Its product of digits (10080) is a multiple of the sum of its prime divisors (280).

678561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (678563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4885 + ... + 5021.

It is an arithmetic number, because the mean of its divisors is an integer number (61824).

2⁶⁷⁸⁵⁶¹ is an apocalyptic number.

It is an amenable number.

678561 is a deficient number, since it is larger than the sum of its proper divisors (310623).

678561 is a wasteful number, since it uses less digits than its factorization.

678561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280.

The product of its digits is 10080, while the sum is 33.

The square root of 678561 is about 823.7481411208. The cubic root of 678561 is about 87.8745198530.

The spelling of 678561 in words is "six hundred seventy-eight thousand, five hundred sixty-one".