688665 has 16 divisors (see below), whose sum is σ = 1138176. Its totient is φ = 355200.

The previous prime is 688661. The next prime is 688669. The reversal of 688665 is 566886.

It is an interprime number because it is at equal distance from previous prime (688661) and next prime (688669).

It is not a de Polignac number, because 688665 - 2² = 688661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 276 + ... + 1205.

It is an arithmetic number, because the mean of its divisors is an integer number (71136).

2⁶⁸⁸⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

688665 is a deficient number, since it is larger than the sum of its proper divisors (449511).

688665 is a wasteful number, since it uses less digits than its factorization.

688665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1520.

The product of its digits is 69120, while the sum is 39.

The square root of 688665 is about 829.8584216600. The cubic root of 688665 is about 88.3085330481.

The spelling of 688665 in words is "six hundred eighty-eight thousand, six hundred sixty-five".