688399 has 4 divisors (see below), whose sum is σ = 690136. Its totient is φ = 686664.

The previous prime is 688397. The next prime is 688403. The reversal of 688399 is 993886.

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 688399 - 2¹ = 688397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688393) 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, 52 + ... + 1174.

It is an arithmetic number, because the mean of its divisors is an integer number (172534).

2⁶⁸⁸³⁹⁹ is an apocalyptic number.

688399 is a deficient number, since it is larger than the sum of its proper divisors (1737).

688399 is a wasteful number, since it uses less digits than its factorization.

688399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1736.

The product of its digits is 93312, while the sum is 43.

The square root of 688399 is about 829.6981378791. The cubic root of 688399 is about 88.2971617259.

The spelling of 688399 in words is "six hundred eighty-eight thousand, three hundred ninety-nine".