999999899 has 4 divisors (see below), whose sum is σ = 1009174320. Its totient is φ = 990825480.

The previous prime is 999999893. The next prime is 999999929. The reversal of 999999899 is 998999999.

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 999999899 - 2⁴ = 999999883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (999999893) 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, 4587047 + ... + 4587264.

It is an arithmetic number, because the mean of its divisors is an integer number (252293580).

Almost surely, 2^999999899 is an apocalyptic number.

999999899 is a deficient number, since it is larger than the sum of its proper divisors (9174421).

999999899 is a wasteful number, since it uses less digits than its factorization.

999999899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9174420.

The product of its digits is 344373768, while the sum is 80.

The square root of 999999899 is about 31622.7750047335. The cubic root of 999999899 is about 999.9999663333. Note that the first 4 decimals are identical.

The spelling of 999999899 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred ninety-nine".