678784 has 16 divisors (see below), whose sum is σ = 1352520. Its totient is φ = 339328.

The previous prime is 678779. The next prime is 678809. The reversal of 678784 is 487876.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2524 + ... + 2779.

2⁶⁷⁸⁷⁸⁴ is an apocalyptic number.

678784 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

678784 is a deficient number, since it is larger than the sum of its proper divisors (673736).

678784 is an equidigital number, since it uses as much as digits as its factorization.

678784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5317 (or 5305 counting only the distinct ones).

The product of its digits is 75264, while the sum is 40.

The square root of 678784 is about 823.8834869082. The cubic root of 678784 is about 87.8841450607.

The spelling of 678784 in words is "six hundred seventy-eight thousand, seven hundred eighty-four".