7818081613 has 2 divisors, whose sum is σ = 7818081614. Its totient is φ = 7818081612.

The previous prime is 7818081599. The next prime is 7818081643. The reversal of 7818081613 is 3161808187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5343317604 + 2474764009 = 73098^2 + 49747^2 .

It is an emirp because it is prime and its reverse (3161808187) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7818081613 - 2¹⁷ = 7817950541 is a prime.

It is a super-2 number, since 2×7818081613² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 7818081613.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7818081643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3909040806 + 3909040807.

It is an arithmetic number, because the mean of its divisors is an integer number (3909040807).

Almost surely, 2^7818081613 is an apocalyptic number.

It is an amenable number.

7818081613 is a deficient number, since it is larger than the sum of its proper divisors (1).

7818081613 is an equidigital number, since it uses as much as digits as its factorization.

7818081613 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64512, while the sum is 43.

The square root of 7818081613 is about 88419.9163820007. The cubic root of 7818081613 is about 1984.7237495802.

The spelling of 7818081613 in words is "seven billion, eight hundred eighteen million, eighty-one thousand, six hundred thirteen".