666403 has 2 divisors, whose sum is σ = 666404. Its totient is φ = 666402.

The previous prime is 666353. The next prime is 666427. The reversal of 666403 is 304666.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666403 - 2¹³ = 658211 is a prime.

It is not a weakly prime, because it can be changed into another prime (666433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333201 + 333202.

It is an arithmetic number, because the mean of its divisors is an integer number (333202).

2⁶⁶⁶⁴⁰³ is an apocalyptic number.

666403 is a deficient number, since it is larger than the sum of its proper divisors (1).

666403 is an equidigital number, since it uses as much as digits as its factorization.

666403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 25.

The square root of 666403 is about 816.3351027611. The cubic root of 666403 is about 87.3465282526.

The spelling of 666403 in words is "six hundred sixty-six thousand, four hundred three".