78813517 has 2 divisors, whose sum is σ = 78813518. Its totient is φ = 78813516.

The previous prime is 78813509. The next prime is 78813523. The reversal of 78813517 is 71531887.

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., 46936201 + 31877316 = 6851^2 + 5646^2 .

It is a cyclic number.

It is not a de Polignac number, because 78813517 - 2³ = 78813509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78813517.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78813587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39406758 + 39406759.

It is an arithmetic number, because the mean of its divisors is an integer number (39406759).

Almost surely, 2^78813517 is an apocalyptic number.

It is an amenable number.

78813517 is a deficient number, since it is larger than the sum of its proper divisors (1).

78813517 is an equidigital number, since it uses as much as digits as its factorization.

78813517 is an odious number, because the sum of its binary digits is odd.

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

The square root of 78813517 is about 8877.6977308309. The cubic root of 78813517 is about 428.7461527306.

The spelling of 78813517 in words is "seventy-eight million, eight hundred thirteen thousand, five hundred seventeen".