6391663 has 2 divisors, whose sum is σ = 6391664. Its totient is φ = 6391662.

The previous prime is 6391607. The next prime is 6391667. The reversal of 6391663 is 3661936.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6391663 - 2¹³ = 6383471 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6391667) 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, 3195831 + 3195832.

It is an arithmetic number, because the mean of its divisors is an integer number (3195832).

Almost surely, 2^6391663 is an apocalyptic number.

6391663 is a deficient number, since it is larger than the sum of its proper divisors (1).

6391663 is an equidigital number, since it uses as much as digits as its factorization.

6391663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 34.

The square root of 6391663 is about 2528.1738468705. The cubic root of 6391663 is about 185.5828997170.

The spelling of 6391663 in words is "six million, three hundred ninety-one thousand, six hundred sixty-three".