8123181491 has 4 divisors (see below), whose sum is σ = 8131000800. Its totient is φ = 8115362184.

The previous prime is 8123181467. The next prime is 8123181527. The reversal of 8123181491 is 1941813218.

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 8123181491 - 2¹⁰ = 8123180467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8123181431) 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, 3908096 + ... + 3910173.

It is an arithmetic number, because the mean of its divisors is an integer number (2032750200).

Almost surely, 2^8123181491 is an apocalyptic number.

8123181491 is a deficient number, since it is larger than the sum of its proper divisors (7819309).

8123181491 is a wasteful number, since it uses less digits than its factorization.

8123181491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7819308.

The product of its digits is 13824, while the sum is 38.

The square root of 8123181491 is about 90128.6940491207. The cubic root of 8123181491 is about 2010.2128839809.

The spelling of 8123181491 in words is "eight billion, one hundred twenty-three million, one hundred eighty-one thousand, four hundred ninety-one".