686187689 has 4 divisors (see below), whose sum is σ = 748568400. Its totient is φ = 623806980.

The previous prime is 686187611. The next prime is 686187701. The reversal of 686187689 is 986781686.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 686187689 - 2⁸ = 686187433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686187289) 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, 31190339 + ... + 31190360.

It is an arithmetic number, because the mean of its divisors is an integer number (187142100).

Almost surely, 2^686187689 is an apocalyptic number.

It is an amenable number.

686187689 is a deficient number, since it is larger than the sum of its proper divisors (62380711).

686187689 is a wasteful number, since it uses less digits than its factorization.

686187689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62380710.

The product of its digits is 6967296, while the sum is 59.

The square root of 686187689 is about 26195.1844620342. The cubic root of 686187689 is about 882.0251606947.

The spelling of 686187689 in words is "six hundred eighty-six million, one hundred eighty-seven thousand, six hundred eighty-nine".