1666218 has 8 divisors (see below), whose sum is σ = 3332448. Its totient is φ = 555404.

The previous prime is 1666213. The next prime is 1666237. The reversal of 1666218 is 8126661.

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

1666218 is an admirable number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1666211) 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 3 ways as a sum of consecutive naturals, for example, 138846 + ... + 138857.

It is an arithmetic number, because the mean of its divisors is an integer number (416556).

2^1666218 is an apocalyptic number.

1666218 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1666218 is a wasteful number, since it uses less digits than its factorization.

1666218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277708.

The product of its digits is 3456, while the sum is 30.

The square root of 1666218 is about 1290.8206691869. The cubic root of 1666218 is about 118.5524701318.

The spelling of 1666218 in words is "one million, six hundred sixty-six thousand, two hundred eighteen".