78561566113 has 2 divisors, whose sum is σ = 78561566114. Its totient is φ = 78561566112.

The previous prime is 78561566099. The next prime is 78561566129. The reversal of 78561566113 is 31166516587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53708989504 + 24852576609 = 231752^2 + 157647^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78561566113 is a prime.

It is not a weakly prime, because it can be changed into another prime (78561566173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39280783056 + 39280783057.

It is an arithmetic number, because the mean of its divisors is an integer number (39280783057).

Almost surely, 2^78561566113 is an apocalyptic number.

It is an amenable number.

78561566113 is a deficient number, since it is larger than the sum of its proper divisors (1).

78561566113 is an equidigital number, since it uses as much as digits as its factorization.

78561566113 is an evil number, because the sum of its binary digits is even.

The product of its digits is 907200, while the sum is 49.

The spelling of 78561566113 in words is "seventy-eight billion, five hundred sixty-one million, five hundred sixty-six thousand, one hundred thirteen".