1668609 has 6 divisors (see below), whose sum is σ = 2410226. Its totient is φ = 1112400.

The previous prime is 1668593. The next prime is 1668617. The reversal of 1668609 is 9068661.

It can be written as a sum of positive squares in only one way, i.e., 1617984 + 50625 = 1272^2 + 225^2 .

It is not a de Polignac number, because 1668609 - 2⁴ = 1668593 is a prime.

It is a Duffinian number.

1668609 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1668619) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 92692 + ... + 92709.

2^1668609 is an apocalyptic number.

It is an amenable number.

1668609 is a deficient number, since it is larger than the sum of its proper divisors (741617).

1668609 is a wasteful number, since it uses less digits than its factorization.

1668609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185407 (or 185404 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 1668609 is about 1291.7464921570. The cubic root of 1668609 is about 118.6091500855.

The spelling of 1668609 in words is "one million, six hundred sixty-eight thousand, six hundred nine".