8123779613 has 4 divisors (see below), whose sum is σ = 8601649020. Its totient is φ = 7645910208.

The previous prime is 8123779603. The next prime is 8123779619. The reversal of 8123779613 is 3169773218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3169773218 = 2 ⋅1584886609.

It can be written as a sum of positive squares in 2 ways, for example, as 5409161209 + 2714618404 = 73547^2 + 52102^2 .

It is not a de Polignac number, because 8123779613 - 2⁶ = 8123779549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8123779619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 238934678 + ... + 238934711.

It is an arithmetic number, because the mean of its divisors is an integer number (2150412255).

Almost surely, 2^8123779613 is an apocalyptic number.

It is an amenable number.

8123779613 is a deficient number, since it is larger than the sum of its proper divisors (477869407).

8123779613 is a wasteful number, since it uses less digits than its factorization.

8123779613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477869406.

The product of its digits is 381024, while the sum is 47.

The square root of 8123779613 is about 90132.0121433001. The cubic root of 8123779613 is about 2010.2622210968.

The spelling of 8123779613 in words is "eight billion, one hundred twenty-three million, seven hundred seventy-nine thousand, six hundred thirteen".