688378 has 4 divisors (see below), whose sum is σ = 1032570. Its totient is φ = 344188.

The previous prime is 688357. The next prime is 688379. The reversal of 688378 is 873886.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 522729 + 165649 = 723^2 + 407^2 .

It is an Ulam number.

It is a zygodrome in base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 688378.

It is not an unprimeable number, because it can be changed into a prime (688379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172093 + ... + 172096.

2⁶⁸⁸³⁷⁸ is an apocalyptic number.

688378 is a deficient number, since it is larger than the sum of its proper divisors (344192).

688378 is a wasteful number, since it uses less digits than its factorization.

688378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344191.

The product of its digits is 64512, while the sum is 40.

The square root of 688378 is about 829.6854825776. The cubic root of 688378 is about 88.2962638651.

The spelling of 688378 in words is "six hundred eighty-eight thousand, three hundred seventy-eight".