79818521513 has 2 divisors, whose sum is σ = 79818521514. Its totient is φ = 79818521512.

The previous prime is 79818521459. The next prime is 79818521579. The reversal of 79818521513 is 31512581897.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58953296809 + 20865224704 = 242803^2 + 144448^2 .

It is an emirp because it is prime and its reverse (31512581897) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 79818521513 - 2³⁰ = 78744779689 is a prime.

It is not a weakly prime, because it can be changed into another prime (79818421513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39909260756 + 39909260757.

It is an arithmetic number, because the mean of its divisors is an integer number (39909260757).

Almost surely, 2^79818521513 is an apocalyptic number.

It is an amenable number.

79818521513 is a deficient number, since it is larger than the sum of its proper divisors (1).

79818521513 is an equidigital number, since it uses as much as digits as its factorization.

79818521513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 604800, while the sum is 50.

The spelling of 79818521513 in words is "seventy-nine billion, eight hundred eighteen million, five hundred twenty-one thousand, five hundred thirteen".