9991000097999 has 4 divisors (see below), whose sum is σ = 10516842208440. Its totient is φ = 9465157987560.

The previous prime is 9991000097977. The next prime is 9991000098041. The reversal of 9991000097999 is 9997900001999.

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 9991000097999 - 2¹⁶ = 9991000032463 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 (9991000091999) 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, 262921055192 + ... + 262921055229.

It is an arithmetic number, because the mean of its divisors is an integer number (2629210552110).

Almost surely, 2^{9991000097999} is an apocalyptic number.

9991000097999 is a deficient number, since it is larger than the sum of its proper divisors (525842110441).

9991000097999 is a wasteful number, since it uses less digits than its factorization.

9991000097999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 525842110440.

The product of its (nonzero) digits is 33480783, while the sum is 71.

The spelling of 9991000097999 in words is "nine trillion, nine hundred ninety-one billion, ninety-seven thousand, nine hundred ninety-nine".