7971538613 has 2 divisors, whose sum is σ = 7971538614. Its totient is φ = 7971538612.

The previous prime is 7971538577. The next prime is 7971538657. The reversal of 7971538613 is 3168351797.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5825810929 + 2145727684 = 76327^2 + 46322^2 .

It is a cyclic number.

It is not a de Polignac number, because 7971538613 - 2²⁰ = 7970490037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7971588613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3985769306 + 3985769307.

It is an arithmetic number, because the mean of its divisors is an integer number (3985769307).

Almost surely, 2^7971538613 is an apocalyptic number.

It is an amenable number.

7971538613 is a deficient number, since it is larger than the sum of its proper divisors (1).

7971538613 is an equidigital number, since it uses as much as digits as its factorization.

7971538613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 952560, while the sum is 50.

The square root of 7971538613 is about 89283.4733475350. The cubic root of 7971538613 is about 1997.6253995020.

The spelling of 7971538613 in words is "seven billion, nine hundred seventy-one million, five hundred thirty-eight thousand, six hundred thirteen".