998999998 has 4 divisors (see below), whose sum is σ = 1498500000. Its totient is φ = 499499998.

The previous prime is 998999971. The next prime is 998999999. The reversal of 998999998 is 899999899.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 899999899 = 3833 ⋅234803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998999999) 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 as a sum of consecutive naturals, namely, 249749998 + ... + 249750001.

It is an arithmetic number, because the mean of its divisors is an integer number (374625000).

Almost surely, 2^998999998 is an apocalyptic number.

998999998 is a deficient number, since it is larger than the sum of its proper divisors (499500002).

998999998 is a wasteful number, since it uses less digits than its factorization.

998999998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499500001.

The product of its digits is 306110016, while the sum is 79.

The square root of 998999998 is about 31606.9612269196. The cubic root of 998999998 is about 999.6665548267. Note that the first 3 decimals are identical.

Subtracting from 998999998 its reverse (899999899), we obtain a palindrome (99000099).

The spelling of 998999998 in words is "nine hundred ninety-eight million, nine hundred ninety-nine thousand, nine hundred ninety-eight".