20012989985509 has 2 divisors, whose sum is σ = 20012989985510. Its totient is φ = 20012989985508.

The previous prime is 20012989985507. The next prime is 20012989985519. The reversal of 20012989985509 is 90558998921002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11326442168484 + 8686547817025 = 3365478^2 + 2947295^2 .

It is a cyclic number.

It is not a de Polignac number, because 20012989985509 - 2¹ = 20012989985507 is a prime.

Together with 20012989985507, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20012989985507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10006494992754 + 10006494992755.

It is an arithmetic number, because the mean of its divisors is an integer number (10006494992755).

Almost surely, 2^{20012989985509} is an apocalyptic number.

It is an amenable number.

20012989985509 is a deficient number, since it is larger than the sum of its proper divisors (1).

20012989985509 is an equidigital number, since it uses as much as digits as its factorization.

20012989985509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41990400, while the sum is 67.

The spelling of 20012989985509 in words is "twenty trillion, twelve billion, nine hundred eighty-nine million, nine hundred eighty-five thousand, five hundred nine".