9911999 has 4 divisors (see below), whose sum is σ = 10008336. Its totient is φ = 9815664.

The previous prime is 9911983. The next prime is 9912017. The reversal of 9911999 is 9991199.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 9911999 - 2⁴ = 9911983 is a prime.

It is a Duffinian number.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9911929) 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, 48014 + ... + 48219.

It is an arithmetic number, because the mean of its divisors is an integer number (2502084).

Almost surely, 2^9911999 is an apocalyptic number.

9911999 is a deficient number, since it is larger than the sum of its proper divisors (96337).

9911999 is a wasteful number, since it uses less digits than its factorization.

9911999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96336.

The product of its digits is 59049, while the sum is 47.

The square root of 9911999 is about 3148.3327333686. The cubic root of 9911999 is about 214.8096313825.

The spelling of 9911999 in words is "nine million, nine hundred eleven thousand, nine hundred ninety-nine".