19905007009 has 2 divisors, whose sum is σ = 19905007010. Its totient is φ = 19905007008.

The previous prime is 19905007007. The next prime is 19905007013. The reversal of 19905007009 is 90070050991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14219847009 + 5685160000 = 119247^2 + 75400^2 .

It is an emirp because it is prime and its reverse (90070050991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19905007009 - 2¹ = 19905007007 is a prime.

Together with 19905007007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (19905007007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9952503504 + 9952503505.

It is an arithmetic number, because the mean of its divisors is an integer number (9952503505).

Almost surely, 2^19905007009 is an apocalyptic number.

It is an amenable number.

19905007009 is a deficient number, since it is larger than the sum of its proper divisors (1).

19905007009 is an equidigital number, since it uses as much as digits as its factorization.

19905007009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25515, while the sum is 40.

The spelling of 19905007009 in words is "nineteen billion, nine hundred five million, seven thousand, nine".