687987209 has 16 divisors (see below), whose sum is σ = 854679168. Its totient is φ = 539246592.

The previous prime is 687987199. The next prime is 687987239. The reversal of 687987209 is 902789786.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687987209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (687987239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25592 + ... + 45065.

It is an arithmetic number, because the mean of its divisors is an integer number (53417448).

Almost surely, 2^687987209 is an apocalyptic number.

It is an amenable number.

687987209 is a deficient number, since it is larger than the sum of its proper divisors (166691959).

687987209 is a wasteful number, since it uses less digits than its factorization.

687987209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70784.

The product of its (nonzero) digits is 3048192, while the sum is 56.

The square root of 687987209 is about 26229.5102699231. The cubic root of 687987209 is about 882.7955215691.

The spelling of 687987209 in words is "six hundred eighty-seven million, nine hundred eighty-seven thousand, two hundred nine".