678724 has 6 divisors (see below), whose sum is σ = 1187774. Its totient is φ = 339360.

The previous prime is 678721. The next prime is 678731. The reversal of 678724 is 427876.

It can be written as a sum of positive squares in only one way, i.e., 577600 + 101124 = 760^2 + 318^2 .

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 678724.

It is not an unprimeable number, because it can be changed into a prime (678721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84837 + ... + 84844.

2⁶⁷⁸⁷²⁴ is an apocalyptic number.

It is an amenable number.

678724 is a deficient number, since it is larger than the sum of its proper divisors (509050).

678724 is a wasteful number, since it uses less digits than its factorization.

678724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169685 (or 169683 counting only the distinct ones).

The product of its digits is 18816, while the sum is 34.

The square root of 678724 is about 823.8470731877. The cubic root of 678724 is about 87.8815555260.

It can be divided in two parts, 67872 and 4, that added together give a palindrome (67876).

The spelling of 678724 in words is "six hundred seventy-eight thousand, seven hundred twenty-four".