999999999799 has 4 divisors (see below), whose sum is σ = 1002188184064. Its totient is φ = 997811815536.

The previous prime is 999999999767. The next prime is 999999999847. The reversal of 999999999799 is 997999999999.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 997999999999 = 164341 ⋅6072739.

It is a cyclic number.

It is not a de Polignac number, because 999999999799 - 2⁵ = 999999999767 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999999999599) 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, 1094091447 + ... + 1094092360.

It is an arithmetic number, because the mean of its divisors is an integer number (250547046016).

Almost surely, 2^999999999799 is an apocalyptic number.

999999999799 is a deficient number, since it is larger than the sum of its proper divisors (2188184265).

999999999799 is a wasteful number, since it uses less digits than its factorization.

999999999799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2188184264.

The product of its digits is 219667417263, while the sum is 106.

The spelling of 999999999799 in words is "nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, seven hundred ninety-nine".