99939999 has 4 divisors (see below), whose sum is σ = 133253336. Its totient is φ = 66626664.

The previous prime is 99939967. The next prime is 99940007. The reversal of 99939999 is 99993999.

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

It is not a de Polignac number, because 99939999 - 2⁵ = 99939967 is a prime.

It is a Duffinian number.

99939999 is a modest number, since divided by 9999 gives 9993 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99939929) 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, 16656664 + ... + 16656669.

It is an arithmetic number, because the mean of its divisors is an integer number (33313334).

Almost surely, 2^99939999 is an apocalyptic number.

99939999 is a deficient number, since it is larger than the sum of its proper divisors (33313337).

99939999 is a wasteful number, since it uses less digits than its factorization.

99939999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33313336.

The product of its digits is 14348907, while the sum is 66.

The square root of 99939999 is about 9996.9994998499. Note that the first 3 decimals coincide. The cubic root of 99939999 is about 464.0660314642.

The spelling of 99939999 in words is "ninety-nine million, nine hundred thirty-nine thousand, nine hundred ninety-nine".