688888889 has 4 divisors (see below), whose sum is σ = 741880356. Its totient is φ = 635897424.

The previous prime is 688888883. The next prime is 688888891. The reversal of 688888889 is 988888886.

It is a happy number.

688888889 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 145998889 + 542890000 = 12083^2 + 23300^2 .

It is a cyclic number.

It is not a de Polignac number, because 688888889 - 2¹² = 688884793 is a prime.

688888889 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (688888883) 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, 26495714 + ... + 26495739.

It is an arithmetic number, because the mean of its divisors is an integer number (185470089).

Almost surely, 2^688888889 is an apocalyptic number.

It is an amenable number.

688888889 is a deficient number, since it is larger than the sum of its proper divisors (52991467).

688888889 is a wasteful number, since it uses less digits than its factorization.

688888889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52991466.

The product of its digits is 113246208, while the sum is 71.

The square root of 688888889 is about 26246.6929154894. The cubic root of 688888889 is about 883.1810188388.

It can be divided in two parts, 68888 and 8889, that added together give a palindrome (77777).

The spelling of 688888889 in words is "six hundred eighty-eight million, eight hundred eighty-eight thousand, eight hundred eighty-nine".