8191999999 has 8 divisors (see below), whose sum is σ = 8615485440. Its totient is φ = 7774123896.

The previous prime is 8191999993. The next prime is 8192000017. The reversal of 8191999999 is 9999991918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 8191999999 - 2¹¹ = 8191997951 is a prime.

It is a Duffinian number.

8191999999 is a modest number, since divided by 99999 gives 81919 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8191999993) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1399339 + ... + 1405180.

It is an arithmetic number, because the mean of its divisors is an integer number (1076935680).

Almost surely, 2^8191999999 is an apocalyptic number.

8191999999 is a deficient number, since it is larger than the sum of its proper divisors (423485441).

8191999999 is a wasteful number, since it uses less digits than its factorization.

8191999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2804669.

The product of its digits is 38263752, while the sum is 73.

The square root of 8191999999 is about 90509.6679863538. The cubic root of 8191999999 is about 2015.8736797498.

The spelling of 8191999999 in words is "eight billion, one hundred ninety-one million, nine hundred ninety-nine thousand, nine hundred ninety-nine".