1666609 has 8 divisors (see below), whose sum is σ = 1951488. Its totient is φ = 1393440.

The previous prime is 1666607. The next prime is 1666619. The reversal of 1666609 is 9066661.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1666609 - 2¹ = 1666607 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1666607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2617 + ... + 3190.

It is an arithmetic number, because the mean of its divisors is an integer number (243936).

2^1666609 is an apocalyptic number.

It is an amenable number.

1666609 is a deficient number, since it is larger than the sum of its proper divisors (284879).

1666609 is an equidigital number, since it uses as much as digits as its factorization.

1666609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5855.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 1666609 is about 1290.9721143386. The cubic root of 1666609 is about 118.5617427060.

The spelling of 1666609 in words is "one million, six hundred sixty-six thousand, six hundred nine".