990999998999 has 4 divisors (see below), whose sum is σ = 991027869336. Its totient is φ = 990972128664.

The previous prime is 990999998981. The next prime is 990999999019. The reversal of 990999998999 is 999899999099.

It is a happy number.

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 990999998999 - 2¹⁶ = 990999933463 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 (990999998099) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13881764 + ... + 13952969.

It is an arithmetic number, because the mean of its divisors is an integer number (247756967334).

Almost surely, 2^990999998999 is an apocalyptic number.

990999998999 is a deficient number, since it is larger than the sum of its proper divisors (27870337).

990999998999 is a wasteful number, since it uses less digits than its factorization.

990999998999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27870336.

The product of its (nonzero) digits is 27894275208, while the sum is 98.

The spelling of 990999998999 in words is "nine hundred ninety billion, nine hundred ninety-nine million, nine hundred ninety-eight thousand, nine hundred ninety-nine".