686989687 has 4 divisors (see below), whose sum is σ = 698633640. Its totient is φ = 675345736.

The previous prime is 686989673. The next prime is 686989697. The reversal of 686989687 is 786989686.

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-686989687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686989697) 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, 5821888 + ... + 5822005.

It is an arithmetic number, because the mean of its divisors is an integer number (174658410).

Almost surely, 2^686989687 is an apocalyptic number.

686989687 is a deficient number, since it is larger than the sum of its proper divisors (11643953).

686989687 is a wasteful number, since it uses less digits than its factorization.

686989687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11643952.

The product of its digits is 62705664, while the sum is 67.

The square root of 686989687 is about 26210.4881106781. The cubic root of 686989687 is about 882.3686561237.

Subtracting 686989687 from its reverse (786989686), we obtain a palindrome (99999999).

The spelling of 686989687 in words is "six hundred eighty-six million, nine hundred eighty-nine thousand, six hundred eighty-seven".