8185191913 has 4 divisors (see below), whose sum is σ = 8467439940. Its totient is φ = 7902943888.

The previous prime is 8185191871. The next prime is 8185191923. The reversal of 8185191913 is 3191915818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1986306624 + 6198885289 = 44568^2 + 78733^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8185191913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8185191923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141123970 + ... + 141124027.

It is an arithmetic number, because the mean of its divisors is an integer number (2116859985).

Almost surely, 2^8185191913 is an apocalyptic number.

It is an amenable number.

8185191913 is a deficient number, since it is larger than the sum of its proper divisors (282248027).

8185191913 is a wasteful number, since it uses less digits than its factorization.

8185191913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282248026.

The product of its digits is 77760, while the sum is 46.

The square root of 8185191913 is about 90472.0504520595. The cubic root of 8185191913 is about 2015.3150841668.

The spelling of 8185191913 in words is "eight billion, one hundred eighty-five million, one hundred ninety-one thousand, nine hundred thirteen".