678765 has 16 divisors (see below), whose sum is σ = 1116288. Its totient is φ = 351936.

The previous prime is 678763. The next prime is 678767. The reversal of 678765 is 567876.

678765 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (678763) and next prime (678767).

It is not a de Polignac number, because 678765 - 2¹ = 678763 is a prime.

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

It is a plaindrome in base 8.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 678765.

It is not an unprimeable number, because it can be changed into a prime (678761) 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, 57 + ... + 1166.

It is an arithmetic number, because the mean of its divisors is an integer number (69768).

2⁶⁷⁸⁷⁶⁵ is an apocalyptic number.

It is an amenable number.

678765 is a deficient number, since it is larger than the sum of its proper divisors (437523).

678765 is a wasteful number, since it uses less digits than its factorization.

678765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1268.

The product of its digits is 70560, while the sum is 39.

The square root of 678765 is about 823.8719560708. The cubic root of 678765 is about 87.8833250579.

Subtracting from 678765 its reverse (567876), we obtain a square (110889 = 333²).

The spelling of 678765 in words is "six hundred seventy-eight thousand, seven hundred sixty-five".