20643938195009 has 2 divisors, whose sum is σ = 20643938195010. Its totient is φ = 20643938195008.

The previous prime is 20643938194987. The next prime is 20643938195021. The reversal of 20643938195009 is 90059183934602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14228761042609 + 6415177152400 = 3772103^2 + 2532820^2 .

It is a cyclic number.

It is not a de Polignac number, because 20643938195009 - 2²⁴ = 20643921417793 is a prime.

It is not a weakly prime, because it can be changed into another prime (20643938195029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10321969097504 + 10321969097505.

It is an arithmetic number, because the mean of its divisors is an integer number (10321969097505).

Almost surely, 2^{20643938195009} is an apocalyptic number.

It is an amenable number.

20643938195009 is a deficient number, since it is larger than the sum of its proper divisors (1).

20643938195009 is an equidigital number, since it uses as much as digits as its factorization.

20643938195009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12597120, while the sum is 59.

The spelling of 20643938195009 in words is "twenty trillion, six hundred forty-three billion, nine hundred thirty-eight million, one hundred ninety-five thousand, nine".