688978 has 8 divisors (see below), whose sum is σ = 1087920. Its totient is φ = 326340.

The previous prime is 688969. The next prime is 688979. The reversal of 688978 is 879886.

688978 is nontrivially palindromic in base 3.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (688979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9028 + ... + 9103.

It is an arithmetic number, because the mean of its divisors is an integer number (135990).

2⁶⁸⁸⁹⁷⁸ is an apocalyptic number.

688978 is a deficient number, since it is larger than the sum of its proper divisors (398942).

688978 is a wasteful number, since it uses less digits than its factorization.

688978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18152.

The product of its digits is 193536, while the sum is 46.

The square root of 688978 is about 830.0469866218. The cubic root of 688978 is about 88.3219098395.

The spelling of 688978 in words is "six hundred eighty-eight thousand, nine hundred seventy-eight".