688715 has 4 divisors (see below), whose sum is σ = 826464. Its totient is φ = 550968.

The previous prime is 688697. The next prime is 688717. The reversal of 688715 is 517886.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 688715 - 2¹⁰ = 687691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688717) 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, 68867 + ... + 68876.

It is an arithmetic number, because the mean of its divisors is an integer number (206616).

2⁶⁸⁸⁷¹⁵ is an apocalyptic number.

688715 is a deficient number, since it is larger than the sum of its proper divisors (137749).

688715 is a wasteful number, since it uses less digits than its factorization.

688715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137748.

The product of its digits is 13440, while the sum is 35.

The square root of 688715 is about 829.8885467338. Note that the first 3 decimals coincide. The cubic root of 688715 is about 88.3106701877.

The spelling of 688715 in words is "six hundred eighty-eight thousand, seven hundred fifteen".