199999081 has 2 divisors, whose sum is σ = 199999082. Its totient is φ = 199999080.

The previous prime is 199999061. The next prime is 199999091. The reversal of 199999081 is 180999991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161061481 + 38937600 = 12691^2 + 6240^2 .

It is a cyclic number.

It is not a de Polignac number, because 199999081 - 2¹¹ = 199997033 is a prime.

It is a super-2 number, since 2×199999081² = 79999264801689122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199999001) 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, 99999540 + 99999541.

It is an arithmetic number, because the mean of its divisors is an integer number (99999541).

Almost surely, 2^199999081 is an apocalyptic number.

It is an amenable number.

199999081 is a deficient number, since it is larger than the sum of its proper divisors (1).

199999081 is an equidigital number, since it uses as much as digits as its factorization.

199999081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 472392, while the sum is 55.

The square root of 199999081 is about 14142.1031321370. The cubic root of 199999081 is about 584.8026519171.

The spelling of 199999081 in words is "one hundred ninety-nine million, nine hundred ninety-nine thousand, eighty-one".