99989999 has 4 divisors (see below), whose sum is σ = 103437960. Its totient is φ = 96542040.

The previous prime is 99989983. The next prime is 99990001. The reversal of 99989999 is 99998999.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 99989999 - 2⁴ = 99989983 is a prime.

It is a Duffinian number.

99989999 is a modest number, since divided by 9999 gives 9998 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99989909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1723937 + ... + 1723994.

It is an arithmetic number, because the mean of its divisors is an integer number (25859490).

Almost surely, 2^99989999 is an apocalyptic number.

99989999 is a deficient number, since it is larger than the sum of its proper divisors (3447961).

99989999 is a wasteful number, since it uses less digits than its factorization.

99989999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3447960.

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

The square root of 99989999 is about 9999.4999374969. The cubic root of 99989999 is about 464.1434093354.

The spelling of 99989999 in words is "ninety-nine million, nine hundred eighty-nine thousand, nine hundred ninety-nine".