1688009 has 4 divisors (see below), whose sum is σ = 1693716. Its totient is φ = 1682304.

The previous prime is 1687999. The next prime is 1688041. The reversal of 1688009 is 9008861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9008861 = 17 ⋅529933.

It can be written as a sum of positive squares in 2 ways, for example, as 727609 + 960400 = 853^2 + 980^2 .

It is a cyclic number.

It is not a de Polignac number, because 1688009 - 2¹⁶ = 1622473 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 (1688069) 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, 2384 + ... + 3009.

It is an arithmetic number, because the mean of its divisors is an integer number (423429).

2^1688009 is an apocalyptic number.

It is an amenable number.

1688009 is a deficient number, since it is larger than the sum of its proper divisors (5707).

1688009 is an equidigital number, since it uses as much as digits as its factorization.

1688009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5706.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 1688009 is about 1299.2340050968. The cubic root of 1688009 is about 119.0670478741.

The spelling of 1688009 in words is "one million, six hundred eighty-eight thousand, nine".