999999999161 has 2 divisors, whose sum is σ = 999999999162. Its totient is φ = 999999999160.

The previous prime is 999999999143. The next prime is 999999999247. The reversal of 999999999161 is 161999999999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 975156250000 + 24843749161 = 987500^2 + 157619^2 .

It is a cyclic number.

It is not a de Polignac number, because 999999999161 - 2¹⁸ = 999999737017 is a prime.

It is not a weakly prime, because it can be changed into another prime (999999999101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999999580 + 499999999581.

It is an arithmetic number, because the mean of its divisors is an integer number (499999999581).

Almost surely, 2^999999999161 is an apocalyptic number.

It is an amenable number.

999999999161 is a deficient number, since it is larger than the sum of its proper divisors (1).

999999999161 is an equidigital number, since it uses as much as digits as its factorization.

999999999161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2324522934, while the sum is 89.

The spelling of 999999999161 in words is "nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, one hundred sixty-one".