8423191681 has 2 divisors, whose sum is σ = 8423191682. Its totient is φ = 8423191680.

The previous prime is 8423191633. The next prime is 8423191709. The reversal of 8423191681 is 1861913248.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8169267456 + 253924225 = 90384^2 + 15935^2 .

It is a cyclic number.

It is not a de Polignac number, because 8423191681 - 2²³ = 8414803073 is a prime.

It is a super-2 number, since 2×8423191681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (8423191631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4211595840 + 4211595841.

It is an arithmetic number, because the mean of its divisors is an integer number (4211595841).

Almost surely, 2^8423191681 is an apocalyptic number.

It is an amenable number.

8423191681 is a deficient number, since it is larger than the sum of its proper divisors (1).

8423191681 is an equidigital number, since it uses as much as digits as its factorization.

8423191681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 43.

The square root of 8423191681 is about 91777.9476835258. The cubic root of 8423191681 is about 2034.6617834646.

The spelling of 8423191681 in words is "eight billion, four hundred twenty-three million, one hundred ninety-one thousand, six hundred eighty-one".