643243010009 has 2 divisors, whose sum is σ = 643243010010. Its totient is φ = 643243010008.

The previous prime is 643243009999. The next prime is 643243010099. The reversal of 643243010009 is 900010342346.

643243010009 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 can be written as a sum of positive squares in only one way, i.e., 630253393225 + 12989616784 = 793885^2 + 113972^2 .

It is a cyclic number.

It is not a de Polignac number, because 643243010009 - 2¹² = 643243005913 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (643243010099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321621505004 + 321621505005.

It is an arithmetic number, because the mean of its divisors is an integer number (321621505005).

Almost surely, 2^643243010009 is an apocalyptic number.

It is an amenable number.

643243010009 is a deficient number, since it is larger than the sum of its proper divisors (1).

643243010009 is an equidigital number, since it uses as much as digits as its factorization.

643243010009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 32.

The spelling of 643243010009 in words is "six hundred forty-three billion, two hundred forty-three million, ten thousand, nine".