688191613 has 4 divisors (see below), whose sum is σ = 688268988. Its totient is φ = 688114240.

The previous prime is 688191607. The next prime is 688191649. The reversal of 688191613 is 316191886.

It is a happy number.

688191613 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, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 197037369 + 491154244 = 14037^2 + 22162^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688191613 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 688191613.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688191653) 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, 23308 + ... + 43813.

It is an arithmetic number, because the mean of its divisors is an integer number (172067247).

Almost surely, 2^688191613 is an apocalyptic number.

It is an amenable number.

688191613 is a deficient number, since it is larger than the sum of its proper divisors (77375).

688191613 is a wasteful number, since it uses less digits than its factorization.

688191613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77374.

The product of its digits is 62208, while the sum is 43.

The square root of 688191613 is about 26233.4064314949. The cubic root of 688191613 is about 882.8829403786.

The spelling of 688191613 in words is "six hundred eighty-eight million, one hundred ninety-one thousand, six hundred thirteen".