999109 has 4 divisors (see below), whose sum is σ = 1007104. Its totient is φ = 991116.

The previous prime is 999101. The next prime is 999133. The reversal of 999109 is 901999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 901999 = 7 ⋅128857.

It is a cyclic number.

It is not a de Polignac number, because 999109 - 2³ = 999101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3807 + ... + 4060.

It is an arithmetic number, because the mean of its divisors is an integer number (251776).

2⁹⁹⁹¹⁰⁹ is an apocalyptic number.

It is an amenable number.

999109 is a deficient number, since it is larger than the sum of its proper divisors (7995).

999109 is a wasteful number, since it uses less digits than its factorization.

999109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7994.

The product of its (nonzero) digits is 6561, while the sum is 37.

The square root of 999109 is about 999.5544007206. The cubic root of 999109 is about 99.9702911747.

The spelling of 999109 in words is "nine hundred ninety-nine thousand, one hundred nine".