687697 has 4 divisors (see below), whose sum is σ = 692080. Its totient is φ = 683316.

The previous prime is 687691. The next prime is 687707. The reversal of 687697 is 796786.

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, and also an emirpimes, since its reverse is a distinct semiprime: 796786 = 2 ⋅398393.

It is a cyclic number.

It is not a de Polignac number, because 687697 - 2¹¹ = 685649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (687691) 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 3 ways as a sum of consecutive naturals, for example, 1947 + ... + 2272.

It is an arithmetic number, because the mean of its divisors is an integer number (173020).

2⁶⁸⁷⁶⁹⁷ is an apocalyptic number.

It is an amenable number.

687697 is a deficient number, since it is larger than the sum of its proper divisors (4383).

687697 is a wasteful number, since it uses less digits than its factorization.

687697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4382.

The product of its digits is 127008, while the sum is 43.

The square root of 687697 is about 829.2749845498. The cubic root of 687697 is about 88.2671376220.

The spelling of 687697 in words is "six hundred eighty-seven thousand, six hundred ninety-seven".