8123811681 has 16 divisors (see below), whose sum is σ = 10873958400. Its totient is φ = 5394810960.

The previous prime is 8123811637. The next prime is 8123811719. The reversal of 8123811681 is 1861183218.

It is not a de Polignac number, because 8123811681 - 2¹⁸ = 8123549537 is a prime.

It is a super-2 number, since 2×8123811681² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (8123811781) 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 in 15 ways as a sum of consecutive naturals, for example, 878520 + ... + 887718.

It is an arithmetic number, because the mean of its divisors is an integer number (679622400).

Almost surely, 2^8123811681 is an apocalyptic number.

It is an amenable number.

8123811681 is a deficient number, since it is larger than the sum of its proper divisors (2750146719).

8123811681 is a wasteful number, since it uses less digits than its factorization.

8123811681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10316.

The product of its digits is 18432, while the sum is 39.

The square root of 8123811681 is about 90132.1900377440. The cubic root of 8123811681 is about 2010.2648662122.

Adding to 8123811681 its reverse (1861183218), we get a palindrome (9984994899).

The spelling of 8123811681 in words is "eight billion, one hundred twenty-three million, eight hundred eleven thousand, six hundred eighty-one".