999109081 has 4 divisors (see below), whose sum is σ = 1004884452. Its totient is φ = 993333712.

The previous prime is 999109061. The next prime is 999109087. The reversal of 999109081 is 180901999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 180901999 = 5407 ⋅33457.

It can be written as a sum of positive squares in 2 ways, for example, as 894967056 + 104142025 = 29916^2 + 10205^2 .

It is a cyclic number.

It is not a de Polignac number, because 999109081 - 2¹³ = 999100889 is a prime.

It is a super-2 number, since 2×999109081² = 1996437911473329122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999109087) 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 in 3 ways as a sum of consecutive naturals, for example, 2887426 + ... + 2887771.

It is an arithmetic number, because the mean of its divisors is an integer number (251221113).

Almost surely, 2^999109081 is an apocalyptic number.

It is an amenable number.

999109081 is a deficient number, since it is larger than the sum of its proper divisors (5775371).

999109081 is a wasteful number, since it uses less digits than its factorization.

999109081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5775370.

The product of its (nonzero) digits is 52488, while the sum is 46.

The square root of 999109081 is about 31608.6867965121. The cubic root of 999109081 is about 999.7029387634.

The spelling of 999109081 in words is "nine hundred ninety-nine million, one hundred nine thousand, eighty-one".