999888999 has 32 divisors (see below), whose sum is σ = 1430161920. Its totient is φ = 620145792.

The previous prime is 999888979. The next prime is 999889027.

999888999 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 999888999 - 2¹⁶ = 999823463 is a prime.

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 (999888979) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 342982 + ... + 345884.

It is an arithmetic number, because the mean of its divisors is an integer number (44692560).

Almost surely, 2^999888999 is an apocalyptic number.

999888999 is a deficient number, since it is larger than the sum of its proper divisors (430272921).

999888999 is a wasteful number, since it uses less digits than its factorization.

999888999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3079.

The product of its digits is 272097792, while the sum is 78.

The square root of 999888999 is about 31621.0214730644. The cubic root of 999888999 is about 999.9629982976.

The spelling of 999888999 in words is "nine hundred ninety-nine million, eight hundred eighty-eight thousand, nine hundred ninety-nine".