1666003 has 2 divisors, whose sum is σ = 1666004. Its totient is φ = 1666002.

The previous prime is 1665997. The next prime is 1666019. The reversal of 1666003 is 3006661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1666003 - 2¹³ = 1657811 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666043) 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 as a sum of consecutive naturals, namely, 833001 + 833002.

It is an arithmetic number, because the mean of its divisors is an integer number (833002).

2^1666003 is an apocalyptic number.

1666003 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666003 is an equidigital number, since it uses as much as digits as its factorization.

1666003 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 1666003 is about 1290.7373861479. The cubic root of 1666003 is about 118.5473707835.

The spelling of 1666003 in words is "one million, six hundred sixty-six thousand, three".