688356 has 18 divisors (see below), whose sum is σ = 1740102. Its totient is φ = 229440.

The previous prime is 688339. The next prime is 688357. The reversal of 688356 is 653886.

It can be written as a sum of positive squares in only one way, i.e., 665856 + 22500 = 816^2 + 150^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 19121 = 688356 / (6 + 8 + 8 + 3 + 5 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 688356.

It is not an unprimeable number, because it can be changed into a prime (688357) by changing a digit.

688356 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9525 + ... + 9596.

2⁶⁸⁸³⁵⁶ is an apocalyptic number.

It is an amenable number.

688356 is an abundant number, since it is smaller than the sum of its proper divisors (1051746).

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

688356 is a wasteful number, since it uses less digits than its factorization.

688356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19131 (or 19126 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 688356 is about 829.6722244357. The cubic root of 688356 is about 88.2953232296.

Subtracting from 688356 its product of digits (34560), we obtain a triangular number (653796 = T₁₁₄₃).

The spelling of 688356 in words is "six hundred eighty-eight thousand, three hundred fifty-six".