9981881909 has 2 divisors, whose sum is σ = 9981881910. Its totient is φ = 9981881908.

The previous prime is 9981881893. The next prime is 9981881947. The reversal of 9981881909 is 9091881899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9646186225 + 335695684 = 98215^2 + 18322^2 .

It is a cyclic number.

It is not a de Polignac number, because 9981881909 - 2⁴ = 9981881893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9981881309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4990940954 + 4990940955.

It is an arithmetic number, because the mean of its divisors is an integer number (4990940955).

Almost surely, 2^9981881909 is an apocalyptic number.

It is an amenable number.

9981881909 is a deficient number, since it is larger than the sum of its proper divisors (1).

9981881909 is an equidigital number, since it uses as much as digits as its factorization.

9981881909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3359232, while the sum is 62.

The square root of 9981881909 is about 99909.3684746330. The cubic root of 9981881909 is about 2153.1327619744.

The spelling of 9981881909 in words is "nine billion, nine hundred eighty-one million, eight hundred eighty-one thousand, nine hundred nine".