688009 has 12 divisors (see below), whose sum is σ = 843600. Its totient is φ = 557928.

The previous prime is 688003. The next prime is 688013. The reversal of 688009 is 900886.

688009 = T₁₂₆ + T₁₂₇ + ... + T₁₈₂.

It is not a de Polignac number, because 688009 - 2⁵ = 687977 is a prime.

It is an Ulam number.

688009 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (688003) 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, 562 + ... + 1300.

It is an arithmetic number, because the mean of its divisors is an integer number (70300).

2⁶⁸⁸⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

688009 is a deficient number, since it is larger than the sum of its proper divisors (155591).

688009 is a wasteful number, since it uses less digits than its factorization.

688009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 772 (or 765 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 688009 is about 829.4630793471. The cubic root of 688009 is about 88.2804841895.

The spelling of 688009 in words is "six hundred eighty-eight thousand, nine".