6644863 has 2 divisors, whose sum is σ = 6644864. Its totient is φ = 6644862.

The previous prime is 6644843. The next prime is 6644873. The reversal of 6644863 is 3684466.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6644863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6644843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3322431 + 3322432.

It is an arithmetic number, because the mean of its divisors is an integer number (3322432).

Almost surely, 2^6644863 is an apocalyptic number.

6644863 is a deficient number, since it is larger than the sum of its proper divisors (1).

6644863 is an equidigital number, since it uses as much as digits as its factorization.

6644863 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 37.

The square root of 6644863 is about 2577.7631776406. The cubic root of 6644863 is about 188.0018013257.

The spelling of 6644863 in words is "six million, six hundred forty-four thousand, eight hundred sixty-three".