688315787 has 4 divisors (see below), whose sum is σ = 688439856. Its totient is φ = 688191720.

The previous prime is 688315769. The next prime is 688315801. The reversal of 688315787 is 787513886.

688315787 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 is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688315787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688315487) 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, 53303 + ... + 64944.

It is an arithmetic number, because the mean of its divisors is an integer number (172109964).

Almost surely, 2^688315787 is an apocalyptic number.

688315787 is a deficient number, since it is larger than the sum of its proper divisors (124069).

688315787 is a wasteful number, since it uses less digits than its factorization.

688315787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124068.

The product of its digits is 2257920, while the sum is 53.

The square root of 688315787 is about 26235.7730398782. The cubic root of 688315787 is about 882.9360382421.

The spelling of 688315787 in words is "six hundred eighty-eight million, three hundred fifteen thousand, seven hundred eighty-seven".