8120806261 has 4 divisors (see below), whose sum is σ = 8121151692. Its totient is φ = 8120460832.

The previous prime is 8120806249. The next prime is 8120806271. The reversal of 8120806261 is 1626080218.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1925542161 + 6195264100 = 43881^2 + 78710^2 .

It is a cyclic number.

It is not a de Polignac number, because 8120806261 - 2²⁵ = 8087251829 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 (8120806201) 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 3 ways as a sum of consecutive naturals, for example, 134656 + ... + 185401.

It is an arithmetic number, because the mean of its divisors is an integer number (2030287923).

Almost surely, 2^8120806261 is an apocalyptic number.

It is an amenable number.

8120806261 is a deficient number, since it is larger than the sum of its proper divisors (345431).

8120806261 is a wasteful number, since it uses less digits than its factorization.

8120806261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345430.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 8120806261 is about 90115.5162055903. The cubic root of 8120806261 is about 2010.0169351642.

Adding to 8120806261 its reverse (1626080218), we get a palindrome (9746886479).

The spelling of 8120806261 in words is "eight billion, one hundred twenty million, eight hundred six thousand, two hundred sixty-one".