8123306781 has 4 divisors (see below), whose sum is σ = 10831075712. Its totient is φ = 5415537852.

The previous prime is 8123306771. The next prime is 8123306803. The reversal of 8123306781 is 1876033218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 8123306781 - 2¹⁸ = 8123044637 is a prime.

It is a super-2 number, since 2×8123306781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8123306761) 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, 1353884461 + ... + 1353884466.

It is an arithmetic number, because the mean of its divisors is an integer number (2707768928).

Almost surely, 2^8123306781 is an apocalyptic number.

It is an amenable number.

8123306781 is a deficient number, since it is larger than the sum of its proper divisors (2707768931).

8123306781 is a wasteful number, since it uses less digits than its factorization.

8123306781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2707768930.

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 8123306781 is about 90129.3891081039. The cubic root of 8123306781 is about 2010.2232189413.

Adding to 8123306781 its reverse (1876033218), we get a palindrome (9999339999).

The spelling of 8123306781 in words is "eight billion, one hundred twenty-three million, three hundred six thousand, seven hundred eighty-one".