20013721544209 has 2 divisors, whose sum is σ = 20013721544210. Its totient is φ = 20013721544208.

The previous prime is 20013721544143. The next prime is 20013721544237. The reversal of 20013721544209 is 90244512731002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14677288899025 + 5336432645184 = 3831095^2 + 2310072^2 .

It is a cyclic number.

It is not a de Polignac number, because 20013721544209 - 2¹¹ = 20013721542161 is a prime.

It is not a weakly prime, because it can be changed into another prime (20013721544009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10006860772104 + 10006860772105.

It is an arithmetic number, because the mean of its divisors is an integer number (10006860772105).

Almost surely, 2^{20013721544209} is an apocalyptic number.

It is an amenable number.

20013721544209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20013721544209 is an equidigital number, since it uses as much as digits as its factorization.

20013721544209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 20013721544209 in words is "twenty trillion, thirteen billion, seven hundred twenty-one million, five hundred forty-four thousand, two hundred nine".