646401563 has 2 divisors, whose sum is σ = 646401564. Its totient is φ = 646401562.

The previous prime is 646401559. The next prime is 646401577. The reversal of 646401563 is 365104646.

646401563 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646401563 - 2² = 646401559 is a prime.

It is not a weakly prime, because it can be changed into another prime (646401533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323200781 + 323200782.

It is an arithmetic number, because the mean of its divisors is an integer number (323200782).

Almost surely, 2^646401563 is an apocalyptic number.

646401563 is a deficient number, since it is larger than the sum of its proper divisors (1).

646401563 is an equidigital number, since it uses as much as digits as its factorization.

646401563 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 646401563 is about 25424.4284694858. The cubic root of 646401563 is about 864.6376300770.

The spelling of 646401563 in words is "six hundred forty-six million, four hundred one thousand, five hundred sixty-three".