1666679 has 8 divisors (see below), whose sum is σ = 1912608. Its totient is φ = 1422720.

The previous prime is 1666657. The next prime is 1666711. The reversal of 1666679 is 9766661.

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-1666679 is a prime.

It is a Duffinian number.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2939 + ... + 3459.

It is an arithmetic number, because the mean of its divisors is an integer number (239076).

2^1666679 is an apocalyptic number.

1666679 is a deficient number, since it is larger than the sum of its proper divisors (245929).

1666679 is an equidigital number, since it uses as much as digits as its factorization.

1666679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 985.

The product of its digits is 81648, while the sum is 41.

The square root of 1666679 is about 1290.9992254064. Note that the first 3 decimals coincide. The cubic root of 1666679 is about 118.5634026046.

The spelling of 1666679 in words is "one million, six hundred sixty-six thousand, six hundred seventy-nine".