1666403 has 2 divisors, whose sum is σ = 1666404. Its totient is φ = 1666402.

The previous prime is 1666397. The next prime is 1666409. The reversal of 1666403 is 3046661.

It is a balanced prime because it is at equal distance from previous prime (1666397) and next prime (1666409).

It is an emirp because it is prime and its reverse (3046661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1666403 - 2⁴ = 1666387 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1666409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833201 + 833202.

It is an arithmetic number, because the mean of its divisors is an integer number (833202).

2^1666403 is an apocalyptic number.

1666403 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666403 is an equidigital number, since it uses as much as digits as its factorization.

1666403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 1666403 is about 1290.8923270358. The cubic root of 1666403 is about 118.5568575919.

The spelling of 1666403 in words is "one million, six hundred sixty-six thousand, four hundred three".