78939786529 has 2 divisors, whose sum is σ = 78939786530. Its totient is φ = 78939786528.

The previous prime is 78939786479. The next prime is 78939786539. The reversal of 78939786529 is 92568793987.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60949734400 + 17990052129 = 246880^2 + 134127^2 .

It is an emirp because it is prime and its reverse (92568793987) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78939786529 is a prime.

It is not a weakly prime, because it can be changed into another prime (78939786539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39469893264 + 39469893265.

It is an arithmetic number, because the mean of its divisors is an integer number (39469893265).

Almost surely, 2^78939786529 is an apocalyptic number.

It is an amenable number.

78939786529 is a deficient number, since it is larger than the sum of its proper divisors (1).

78939786529 is an equidigital number, since it uses as much as digits as its factorization.

78939786529 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 411505920, while the sum is 73.

The spelling of 78939786529 in words is "seventy-eight billion, nine hundred thirty-nine million, seven hundred eighty-six thousand, five hundred twenty-nine".