688491 has 12 divisors (see below), whose sum is σ = 1001832. Its totient is φ = 455616.

The previous prime is 688477. The next prime is 688511. The reversal of 688491 is 194886.

It is a happy number.

It is not a de Polignac number, because 688491 - 2¹³ = 680299 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 688491.

It is not an unprimeable number, because it can be changed into a prime (688411) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1875 + ... + 2211.

It is an arithmetic number, because the mean of its divisors is an integer number (83486).

2⁶⁸⁸⁴⁹¹ is an apocalyptic number.

688491 is a deficient number, since it is larger than the sum of its proper divisors (313341).

688491 is a wasteful number, since it uses less digits than its factorization.

688491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570 (or 567 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 688491 is about 829.7535778772. The cubic root of 688491 is about 88.3010949957.

The spelling of 688491 in words is "six hundred eighty-eight thousand, four hundred ninety-one".