688649587 has 4 divisors (see below), whose sum is σ = 707261776. Its totient is φ = 670037400.

The previous prime is 688649579. The next prime is 688649597. The reversal of 688649587 is 785946886.

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

It is a cyclic number.

It is not a de Polignac number, because 688649587 - 2³ = 688649579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688649537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9306039 + ... + 9306112.

It is an arithmetic number, because the mean of its divisors is an integer number (176815444).

Almost surely, 2^688649587 is an apocalyptic number.

688649587 is a deficient number, since it is larger than the sum of its proper divisors (18612189).

688649587 is a wasteful number, since it uses less digits than its factorization.

688649587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18612188.

The product of its digits is 23224320, while the sum is 61.

The square root of 688649587 is about 26242.1338118683. The cubic root of 688649587 is about 883.0787423254.

The spelling of 688649587 in words is "six hundred eighty-eight million, six hundred forty-nine thousand, five hundred eighty-seven".