99999998 has 16 divisors (see below), whose sum is σ = 178882560. Its totient is φ = 40993656.

The previous prime is 99999989. The next prime is 100000007. The reversal of 99999998 is 89999999.

It is an interprime number because it is at equal distance from previous prime (99999989) and next prime (100000007).

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154958 + ... + 155601.

It is an arithmetic number, because the mean of its divisors is an integer number (11180160).

Almost surely, 2^99999998 is an apocalyptic number.

99999998 is a deficient number, since it is larger than the sum of its proper divisors (78882562).

99999998 is a wasteful number, since it uses less digits than its factorization.

99999998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310591.

The product of its digits is 38263752, while the sum is 71.

The square root of 99999998 is about 9999.9999000000. Note that the first 4 decimals coincide. The cubic root of 99999998 is about 464.1588802669.

Subtracting from 99999998 its reverse (89999999), we obtain a palindrome (9999999).

The spelling of 99999998 in words is "ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-eight".