99879999 has 4 divisors (see below), whose sum is σ = 133173336. Its totient is φ = 66586664.

The previous prime is 99879991. The next prime is 99880003. The reversal of 99879999 is 99997899.

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 99879999 - 2³ = 99879991 is a prime.

99879999 is a modest number, since divided by 9999 gives 9987 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99879991) 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, 16646664 + ... + 16646669.

It is an arithmetic number, because the mean of its divisors is an integer number (33293334).

Almost surely, 2^99879999 is an apocalyptic number.

99879999 is a deficient number, since it is larger than the sum of its proper divisors (33293337).

99879999 is a wasteful number, since it uses less digits than its factorization.

99879999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33293336.

The product of its digits is 29760696, while the sum is 69.

The square root of 99879999 is about 9993.9981488892. The cubic root of 99879999 is about 463.9731439445.

The spelling of 99879999 in words is "ninety-nine million, eight hundred seventy-nine thousand, nine hundred ninety-nine".