1666663 has 12 divisors (see below), whose sum is σ = 1817440. Its totient is φ = 1527552.

The previous prime is 1666657. The next prime is 1666711. The reversal of 1666663 is 3666661.

It is a happy number.

It is not a de Polignac number, because 1666663 - 2⁹ = 1666151 is a prime.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21058 + ... + 21136.

2^1666663 is an apocalyptic number.

1666663 is a deficient number, since it is larger than the sum of its proper divisors (150777).

1666663 is an equidigital number, since it uses as much as digits as its factorization.

1666663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186 (or 169 counting only the distinct ones).

The product of its digits is 23328, while the sum is 34.

The square root of 1666663 is about 1290.9930286411. The cubic root of 1666663 is about 118.5630232033.

The spelling of 1666663 in words is "one million, six hundred sixty-six thousand, six hundred sixty-three".