668784 has 20 divisors (see below), whose sum is σ = 1727816. Its totient is φ = 222912.

The previous prime is 668761. The next prime is 668791. The reversal of 668784 is 487866.

It is a congruent number.

It is an unprimeable number.

668784 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6919 + ... + 7014.

2⁶⁶⁸⁷⁸⁴ is an apocalyptic number.

It is an amenable number.

668784 is an abundant number, since it is smaller than the sum of its proper divisors (1059032).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

668784 is a wasteful number, since it uses less digits than its factorization.

668784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13944 (or 13938 counting only the distinct ones).

The product of its digits is 64512, while the sum is 39.

The square root of 668784 is about 817.7921496322. The cubic root of 668784 is about 87.4504317892.

The spelling of 668784 in words is "six hundred sixty-eight thousand, seven hundred eighty-four".