998599999 has 4 divisors (see below), whose sum is σ = 998664336. Its totient is φ = 998535664.

The previous prime is 998599997. The next prime is 998600003. The reversal of 998599999 is 999995899.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 999995899 = 7 ⋅142856557.

It is a cyclic number.

It is not a de Polignac number, because 998599999 - 2¹ = 998599997 is a prime.

It is a Duffinian number.

998599999 is a modest number, since divided by 99999 gives 9985 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998599997) 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 in 3 ways as a sum of consecutive naturals, for example, 7062 + ... + 45244.

It is an arithmetic number, because the mean of its divisors is an integer number (249666084).

Almost surely, 2^998599999 is an apocalyptic number.

998599999 is a deficient number, since it is larger than the sum of its proper divisors (64337).

998599999 is a wasteful number, since it uses less digits than its factorization.

998599999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64336.

The product of its digits is 191318760, while the sum is 76.

The square root of 998599999 is about 31600.6328892318. The cubic root of 998599999 is about 999.5331150524.

The spelling of 998599999 in words is "nine hundred ninety-eight million, five hundred ninety-nine thousand, nine hundred ninety-nine".