78815713 has 2 divisors, whose sum is σ = 78815714. Its totient is φ = 78815712.

The previous prime is 78815557. The next prime is 78815729. The reversal of 78815713 is 31751887.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70006689 + 8809024 = 8367^2 + 2968^2 .

It is an emirp because it is prime and its reverse (31751887) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78815713 is a prime.

It is not a weakly prime, because it can be changed into another prime (78815753) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39407856 + 39407857.

It is an arithmetic number, because the mean of its divisors is an integer number (39407857).

Almost surely, 2^78815713 is an apocalyptic number.

It is an amenable number.

78815713 is a deficient number, since it is larger than the sum of its proper divisors (1).

78815713 is an equidigital number, since it uses as much as digits as its factorization.

78815713 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47040, while the sum is 40.

The square root of 78815713 is about 8877.8214106840. The cubic root of 78815713 is about 428.7501347794.

The spelling of 78815713 in words is "seventy-eight million, eight hundred fifteen thousand, seven hundred thirteen".