9181819091917 has 2 divisors, whose sum is σ = 9181819091918. Its totient is φ = 9181819091916.

The previous prime is 9181819091899. The next prime is 9181819091971. The reversal of 9181819091917 is 7191909181819.

Together with next prime (9181819091971) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5732222370436 + 3449596721481 = 2394206^2 + 1857309^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9181819091917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9181814091917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4590909545958 + 4590909545959.

It is an arithmetic number, because the mean of its divisors is an integer number (4590909545959).

Almost surely, 2^{9181819091917} is an apocalyptic number.

It is an amenable number.

9181819091917 is a deficient number, since it is larger than the sum of its proper divisors (1).

9181819091917 is an equidigital number, since it uses as much as digits as its factorization.

9181819091917 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2939328, while the sum is 64.

The spelling of 9181819091917 in words is "nine trillion, one hundred eighty-one billion, eight hundred nineteen million, ninety-one thousand, nine hundred seventeen".