20205781916069 has 2 divisors, whose sum is σ = 20205781916070. Its totient is φ = 20205781916068.

The previous prime is 20205781916063. The next prime is 20205781916077. The reversal of 20205781916069 is 96061918750202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11012375880100 + 9193406035969 = 3318490^2 + 3032063^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20205781916069 is a prime.

It is a super-2 number, since 2×20205781916069² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20205781916063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10102890958034 + 10102890958035.

It is an arithmetic number, because the mean of its divisors is an integer number (10102890958035).

Almost surely, 2^{20205781916069} is an apocalyptic number.

It is an amenable number.

20205781916069 is a deficient number, since it is larger than the sum of its proper divisors (1).

20205781916069 is an equidigital number, since it uses as much as digits as its factorization.

20205781916069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3265920, while the sum is 56.

The spelling of 20205781916069 in words is "twenty trillion, two hundred five billion, seven hundred eighty-one million, nine hundred sixteen thousand, sixty-nine".