643513005409 has 2 divisors, whose sum is σ = 643513005410. Its totient is φ = 643513005408.

The previous prime is 643513005403. The next prime is 643513005493. The reversal of 643513005409 is 904500315346.

643513005409 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., 629293158400 + 14219847009 = 793280^2 + 119247^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643513005409 is a prime.

It is not a weakly prime, because it can be changed into another prime (643513005403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321756502704 + 321756502705.

It is an arithmetic number, because the mean of its divisors is an integer number (321756502705).

Almost surely, 2^643513005409 is an apocalyptic number.

It is an amenable number.

643513005409 is a deficient number, since it is larger than the sum of its proper divisors (1).

643513005409 is an equidigital number, since it uses as much as digits as its factorization.

643513005409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 194400, while the sum is 40.

The spelling of 643513005409 in words is "six hundred forty-three billion, five hundred thirteen million, five thousand, four hundred nine".