19810106909 has 2 divisors, whose sum is σ = 19810106910. Its totient is φ = 19810106908.

The previous prime is 19810106903. The next prime is 19810106929. The reversal of 19810106909 is 90960101891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19802681284 + 7425625 = 140722^2 + 2725^2 .

It is an emirp because it is prime and its reverse (90960101891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19810106909 - 2¹² = 19810102813 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19810106909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19810106903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9905053454 + 9905053455.

It is an arithmetic number, because the mean of its divisors is an integer number (9905053455).

Almost surely, 2^19810106909 is an apocalyptic number.

It is an amenable number.

19810106909 is a deficient number, since it is larger than the sum of its proper divisors (1).

19810106909 is an equidigital number, since it uses as much as digits as its factorization.

19810106909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 44.

The spelling of 19810106909 in words is "nineteen billion, eight hundred ten million, one hundred six thousand, nine hundred nine".