8191999993 has 2 divisors, whose sum is σ = 8191999994. Its totient is φ = 8191999992.

The previous prime is 8191999987. The next prime is 8192000017. The reversal of 8191999993 is 3999991918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5799127104 + 2392872889 = 76152^2 + 48917^2 .

It is a cyclic number.

It is not a de Polignac number, because 8191999993 - 2²¹ = 8189902841 is a prime.

It is not a weakly prime, because it can be changed into another prime (8191999693) 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 as a sum of consecutive naturals, namely, 4095999996 + 4095999997.

It is an arithmetic number, because the mean of its divisors is an integer number (4095999997).

Almost surely, 2^8191999993 is an apocalyptic number.

It is an amenable number.

8191999993 is a deficient number, since it is larger than the sum of its proper divisors (1).

8191999993 is an equidigital number, since it uses as much as digits as its factorization.

8191999993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12754584, while the sum is 67.

The square root of 8191999993 is about 90509.6679532082. The cubic root of 8191999993 is about 2015.8736792576.

The spelling of 8191999993 in words is "eight billion, one hundred ninety-one million, nine hundred ninety-nine thousand, nine hundred ninety-three".