6403 has 4 divisors (see below), whose sum is σ = 6760. Its totient is φ = 6048.

The previous prime is 6397. The next prime is 6421. The reversal of 6403 is 3046.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3046 = 2 ⋅1523.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6403 is a prime.

It is a magnanimous number.

It is a Duffinian number.

It is a plaindrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (6473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 150 + ... + 187.

It is an arithmetic number, because the mean of its divisors is an integer number (1690).

6403 is a deficient number, since it is larger than the sum of its proper divisors (357).

6403 is a wasteful number, since it uses less digits than its factorization.

6403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 6403 is about 80.0187478032. The cubic root of 6403 is about 18.5692558743.

Adding to 6403 its reverse (3046), we get a palindrome (9449).

The spelling of 6403 in words is "six thousand, four hundred three".