643565347 has 2 divisors, whose sum is σ = 643565348. Its totient is φ = 643565346.

The previous prime is 643565291. The next prime is 643565353. The reversal of 643565347 is 743565346.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643565347 is a prime.

It is not a weakly prime, because it can be changed into another prime (643565357) 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, 321782673 + 321782674.

It is an arithmetic number, because the mean of its divisors is an integer number (321782674).

Almost surely, 2^643565347 is an apocalyptic number.

643565347 is a deficient number, since it is larger than the sum of its proper divisors (1).

643565347 is an equidigital number, since it uses as much as digits as its factorization.

643565347 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 907200, while the sum is 43.

The square root of 643565347 is about 25368.5897716054. The cubic root of 643565347 is about 863.3711858930.

Subtracting 643565347 from its reverse (743565346), we obtain a palindrome (99999999).

The spelling of 643565347 in words is "six hundred forty-three million, five hundred sixty-five thousand, three hundred forty-seven".