9999998 has 4 divisors (see below), whose sum is σ = 15000000.
Its totient is φ = 4999998.
The previous prime is 9999991. The next prime is 10000019. The reversal of 9999998 is 8999999.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8999999 = 2999 ⋅3001.
It is a nialpdrome in base 10.
It is a self number, because there is not a number n which added to its sum of digits gives 9999998.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (9999991) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2499998 + ... + 2500001.
It is an arithmetic number, because the mean of its divisors is an integer number (3750000).
Almost surely, 29999998 is an apocalyptic number.
9999998 is a deficient number, since it is larger than the sum of its proper divisors (5000002).
9999998 is a wasteful number, since it uses less digits than its factorization.
9999998 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 5000001.
The product of its digits is 4251528, while the sum is 62.
The square root of 9999998 is about 3162.2773439406.
The cubic root of 9999998 is about 215.4434546403.
Subtracting from 9999998 its reverse (8999999), we obtain a palindrome (999999).
The spelling of 9999998 in words is "nine million, nine hundred ninety-nine thousand, nine hundred ninety-eight".