1668689 has 8 divisors (see below), whose sum is σ = 1883520. Its totient is φ = 1464400.

The previous prime is 1668683. The next prime is 1668721. The reversal of 1668689 is 9868661.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668689 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1668683) 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, 2297 + ... + 2934.

It is an arithmetic number, because the mean of its divisors is an integer number (235440).

2^1668689 is an apocalyptic number.

It is an amenable number.

1668689 is a deficient number, since it is larger than the sum of its proper divisors (214831).

1668689 is a wasteful number, since it uses less digits than its factorization.

1668689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5271.

The product of its digits is 124416, while the sum is 44.

The square root of 1668689 is about 1291.7774576141. Note that the first 3 decimals coincide. The cubic root of 1668689 is about 118.6110455926.

The spelling of 1668689 in words is "one million, six hundred sixty-eight thousand, six hundred eighty-nine".