9919781161 has 2 divisors, whose sum is σ = 9919781162. Its totient is φ = 9919781160.

The previous prime is 9919781153. The next prime is 9919781167. The reversal of 9919781161 is 1611879199.

9919781161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9800010025 + 119771136 = 98995^2 + 10944^2 .

It is a cyclic number.

It is not a de Polignac number, because 9919781161 - 2³ = 9919781153 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 9919781099 and 9919781108.

It is not a weakly prime, because it can be changed into another prime (9919781167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4959890580 + 4959890581.

It is an arithmetic number, because the mean of its divisors is an integer number (4959890581).

Almost surely, 2^9919781161 is an apocalyptic number.

It is an amenable number.

9919781161 is a deficient number, since it is larger than the sum of its proper divisors (1).

9919781161 is an equidigital number, since it uses as much as digits as its factorization.

9919781161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 244944, while the sum is 52.

The square root of 9919781161 is about 99598.0981796339. The cubic root of 9919781161 is about 2148.6583416702.

The spelling of 9919781161 in words is "nine billion, nine hundred nineteen million, seven hundred eighty-one thousand, one hundred sixty-one".