6645663 has 24 divisors (see below), whose sum is σ = 9929088. Its totient is φ = 4281552.

The previous prime is 6645641. The next prime is 6645677. The reversal of 6645663 is 3665466.

6645663 is a `hidden beast` number, since 6 + 645 + 6 + 6 + 3 = 666.

It is not a de Polignac number, because 6645663 - 2⁹ = 6645151 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640663) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62056 + ... + 62162.

It is an arithmetic number, because the mean of its divisors is an integer number (413712).

Almost surely, 2^6645663 is an apocalyptic number.

6645663 is a deficient number, since it is larger than the sum of its proper divisors (3283425).

6645663 is a wasteful number, since it uses less digits than its factorization.

6645663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283 (or 280 counting only the distinct ones).

The product of its digits is 77760, while the sum is 36.

The square root of 6645663 is about 2577.9183462631. The cubic root of 6645663 is about 188.0093457705.

The spelling of 6645663 in words is "six million, six hundred forty-five thousand, six hundred sixty-three".